diff --git a/.github/dependabot.yml b/.github/dependabot.yaml
similarity index 100%
rename from .github/dependabot.yml
rename to .github/dependabot.yaml
diff --git a/.github/workflows/full_ci.yml b/.github/workflows/ci.yaml
similarity index 51%
rename from .github/workflows/full_ci.yml
rename to .github/workflows/ci.yaml
index 3d60b36c61a55..8fbbed08a1eca 100644
--- a/.github/workflows/full_ci.yml
+++ b/.github/workflows/ci.yaml
@@ -1,4 +1,4 @@
-name: full CI
+name: CI
 
 on:
   merge_group:
@@ -9,153 +9,94 @@ env:
   CARGO_TERM_VERBOSE: true
   LIBC_CI: 1
 
+defaults:
+  run:
+    shell: bash
+
 jobs:
   style_check:
     name: Style check
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-24.04
     steps:
       - uses: actions/checkout@v4
       - name: Setup Rust toolchain
-        run: sh ./ci/install-rust.sh
+        run: ./ci/install-rust.sh
       - name: Check style
-        run: sh ci/style.sh
+        run: ./ci/style.sh
 
-  build_channels_linux:
-    name: Build Channels Linux
-    runs-on: ubuntu-22.04
-    env:
-      OS: linux
+  # This runs `cargo build --target ...` for all T1 and T2 targets`
+  verify_build:
+    name: Verify build
     strategy:
-      fail-fast: true
-      max-parallel: 5
       matrix:
-        toolchain:
-          - stable
-          - beta
-          - nightly
-          - 1.63.0
-    steps:
-      - uses: actions/checkout@v4
-      - name: Setup Rust toolchain
-        run: TOOLCHAIN=${{ matrix.toolchain }} sh ./ci/install-rust.sh
-      - name: Execute build.sh
-        run: TOOLCHAIN=${{ matrix.toolchain }} sh ./ci/build.sh
-
-  build_channels_macos:
-    name: Build Channels macOS
-    needs: macos
+        toolchain: [stable, nightly, 1.63.0]
+        os: [ubuntu-24.04, macos-14, windows-2022]
+        include:
+          - toolchain: beta
+            os: ubuntu-24.04
+    runs-on: ${{ matrix.os }}
     env:
-      OS: macos
-    strategy:
-      fail-fast: true
-      max-parallel: 4
-      matrix:
-        target:
-          - { toolchain: stable, os: macos-14 }
-          - { toolchain: beta, os: macos-14 }
-          - { toolchain: nightly, os: macos-14 }
-          - { toolchain: 1.63.0, os: macos-14 }
-    runs-on: ${{ matrix.target.os }}
+      TOOLCHAIN: ${{ matrix.toolchain }}
     steps:
       - uses: actions/checkout@v4
       - name: Setup Rust toolchain
-        run: TOOLCHAIN=${{ matrix.target.toolchain }} sh ./ci/install-rust.sh
+        run: ./ci/install-rust.sh
       - name: Execute build.sh
-        run: TOOLCHAIN=${{ matrix.target.toolchain }} sh ./ci/build.sh
+        run: ./ci/verify-build.sh
 
-  build_channels_windows:
-    name: Build Channels Windows
-    runs-on: windows-2022
-    env:
-      OS: windows
-    strategy:
-      fail-fast: true
-      matrix:
-        toolchain:
-          - 1.63.0
-          - stable
-    steps:
-      - uses: actions/checkout@v4
-      - name: Self-update rustup
-        run: rustup self update
-        shell: bash
-      - name: Execute build.sh
-        run: TOOLCHAIN=${{ matrix.toolchain }} sh ./ci/build.sh
-        shell: bash
-
-  macos:
-    name: macOS
-    runs-on: macos-14
+  test_tier1:
+    name: Test tier1
     strategy:
-      fail-fast: true
-      matrix:
-        target:
-          - aarch64-apple-darwin
-    steps:
-      - uses: actions/checkout@v4
-      - name: Setup Rust toolchain
-        run: TARGET=${{ matrix.target }} sh ./ci/install-rust.sh
-      - name: Execute run.sh
-        run: sh ./ci/run.sh ${{ matrix.target }}
-
-  windows:
-    name: Windows
-    runs-on: windows-2022
-    env:
-      OS: windows
-    strategy:
-      fail-fast: true
       matrix:
         include:
+          - target: i686-unknown-linux-gnu
+            docker: true
+            os: ubuntu-24.04
+          - target: x86_64-unknown-linux-gnu
+            docker: true
+            os: ubuntu-24.04
+          - target: aarch64-apple-darwin
+            os: macos-14
           - target: x86_64-pc-windows-gnu
+            os: windows-2022
             env:
               ARCH_BITS: 64
               ARCH: x86_64
           - target: x86_64-pc-windows-msvc
+            os: windows-2022
           # FIXME: It currently causes segfaults.
           #- target: i686-pc-windows-gnu
           #  env:
           #    ARCH_BITS: 32
           #    ARCH: i686
           - target: i686-pc-windows-msvc
-    steps:
-      - uses: actions/checkout@v4
-      - name: Self-update rustup
-        run: rustup self update
-        shell: bash
-      - name: Setup Rust toolchain
-        run: TARGET=${{ matrix.target }} sh ./ci/install-rust.sh
-        shell: bash
-      - name: Execute run.sh
-        run: sh ./ci/run.sh ${{ matrix.target }}
-        shell: bash
-
-  
-  docker_linux_tier1:
-    name: Docker Linux Tier1
-    runs-on: ubuntu-22.04
-    strategy:
-      fail-fast: true
-      matrix:
-        target:
-          - i686-unknown-linux-gnu
-          - x86_64-unknown-linux-gnu
+            os: windows-2022
+    runs-on: ${{ matrix.os }}
+    env:
+      TARGET: ${{ matrix.target }}
     steps:
       - uses: actions/checkout@v4
       - name: Setup Rust toolchain
-        run: TARGET=${{ matrix.target }} sh ./ci/install-rust.sh
-      - name: Execute run-docker.sh
-        run: sh ./ci/run-docker.sh ${{ matrix.target }}
+        run: ./ci/install-rust.sh
+      - name: Run natively
+        if: "!matrix.docker"
+        run: ./ci/run.sh ${{ matrix.target }}
+      - name: Run in Docker
+        if: "matrix.docker"
+        run: ./ci/run-docker.sh ${{ matrix.target }}
 
-  docker_linux_tier2:
-    name: Docker Linux Tier2
-    needs: [docker_linux_tier1, style_check]
-    runs-on: ubuntu-22.04
+  test_tier2:
+    name: Test tier2
+    needs: [test_tier1, style_check]
+    runs-on: ubuntu-24.04
     strategy:
       fail-fast: true
       max-parallel: 12
       matrix:
         target:
+          # FIXME(sparc): this takes much longer to run than any other job, put
+          # it first to make sure it gets a head start.
+          - sparc64-unknown-linux-gnu
           - aarch64-linux-android
           - aarch64-unknown-linux-gnu
           - aarch64-unknown-linux-musl
@@ -169,12 +110,11 @@ jobs:
           - powerpc-unknown-linux-gnu
           - powerpc64-unknown-linux-gnu
           - powerpc64le-unknown-linux-gnu
-          - s390x-unknown-linux-gnu
           - riscv64gc-unknown-linux-gnu
+          - s390x-unknown-linux-gnu
+          - wasm32-unknown-emscripten
           - wasm32-wasip1
           - wasm32-wasip2
-          - sparc64-unknown-linux-gnu
-          - wasm32-unknown-emscripten
           - x86_64-linux-android
           # FIXME: Exec format error (os error 8)
           # - x86_64-unknown-linux-gnux32
@@ -182,15 +122,18 @@ jobs:
           # FIXME: It seems some items in `src/unix/mod.rs`
           # aren't defined on redox actually.
           # - x86_64-unknown-redox
+    env:
+      TARGET: ${{ matrix.target }}
     steps:
       - uses: actions/checkout@v4
       - name: Setup Rust toolchain
-        run: TARGET=${{ matrix.target }} sh ./ci/install-rust.sh
+        run: ./ci/install-rust.sh
       - name: Execute run-docker.sh
-        run: sh ./ci/run-docker.sh ${{ matrix.target }}
+        run: ./ci/run-docker.sh ${{ matrix.target }}
 
-  solaris:
-    name: Solaris
+  test_tier2_vm:
+    name: Test tier2 VM
+    needs: [test_tier1, style_check]
     runs-on: ubuntu-latest
     strategy:
       fail-fast: true
@@ -207,22 +150,23 @@ jobs:
           mem: 4096
           copyback: false
           prepare: |
+            set -x
             source <(curl -s https://raw.githubusercontent.com/psumbera/solaris-rust/refs/heads/main/sh.rust-web-install)
-            echo "~~~~ rustc --version ~~~~"
             rustc --version
-            echo "~~~~ Solaris-version ~~~~"
             uname -a
           run: |
             export PATH=$HOME/.rust_solaris/bin:$PATH
-            bash ./ci/run.sh ${{ matrix.target }}
+            ./ci/run.sh ${{ matrix.target }}
 
   check_cfg:
     name: "Check #[cfg]s"
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-24.04
+    env:
+      TOOLCHAIN: nightly
     steps:
       - uses: actions/checkout@v4
       - name: Setup Rust toolchain
-        run: TOOLCHAIN=nightly sh ./ci/install-rust.sh
+        run: ./ci/install-rust.sh
       - name: Build with check-cfg
         run: LIBC_CHECK_CFG=1 cargo build -Z unstable-options -Z check-cfg
 
@@ -230,17 +174,13 @@ jobs:
   # protection, rather than having to add each job separately.
   success:
     name: success
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-24.04
     needs:
-      - docker_linux_tier1
-      - docker_linux_tier2
-      - macos
-      - windows
-      - solaris
       - style_check
-      - build_channels_linux
-      - build_channels_macos
-      - build_channels_windows
+      - test_tier1
+      - test_tier2
+      - test_tier2_vm
+      - verify_build
     # Github branch protection is exceedingly silly and treats "jobs skipped because a dependency
     # failed" as success. So we have to do some contortions to ensure the job fails if any of its
     # dependencies fails.
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 2090a0aaa689e..74f49f3e7bb04 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -93,7 +93,7 @@ We have two automated tests running on
   - `cd libc-test && cargo test`
   - Use the `skip_*()` functions in `build.rs` if you really need a workaround.
 2. Style checker
-  - [`sh ci/style.sh`](https://github.com/rust-lang/libc/blob/main/ci/style.sh)
+  - [`./ci/style.sh`](https://github.com/rust-lang/libc/blob/main/ci/style.sh)
 
 ## Breaking change policy
 
diff --git a/ci/android-install-ndk.sh b/ci/android-install-ndk.sh
old mode 100644
new mode 100755
diff --git a/ci/android-install-sdk.sh b/ci/android-install-sdk.sh
old mode 100644
new mode 100755
diff --git a/ci/android-sysimage.sh b/ci/android-sysimage.sh
old mode 100644
new mode 100755
diff --git a/ci/docker/aarch64-linux-android/Dockerfile b/ci/docker/aarch64-linux-android/Dockerfile
index d6927e5cc80ec..dfd63718a9d0d 100644
--- a/ci/docker/aarch64-linux-android/Dockerfile
+++ b/ci/docker/aarch64-linux-android/Dockerfile
@@ -20,8 +20,8 @@ COPY android* /android/
 ENV ANDROID_ARCH=aarch64
 ENV PATH=$PATH:/android/linux-x86_64/bin:/android/sdk/cmdline-tools/tools:/android/sdk/platform-tools
 
-RUN sh /android/android-install-ndk.sh
-RUN sh /android/android-install-sdk.sh $ANDROID_ARCH
+RUN /android/android-install-ndk.sh
+RUN /android/android-install-sdk.sh $ANDROID_ARCH
 RUN mv /root/.android /tmp
 RUN chmod 777 -R /tmp/.android
 RUN chmod 755 /android/sdk/cmdline-tools/tools/* /android/sdk/emulator/qemu/linux-x86_64/*
diff --git a/ci/docker/aarch64-unknown-linux-musl/Dockerfile b/ci/docker/aarch64-unknown-linux-musl/Dockerfile
index fd4c1e28f2525..65932bd48cfac 100644
--- a/ci/docker/aarch64-unknown-linux-musl/Dockerfile
+++ b/ci/docker/aarch64-unknown-linux-musl/Dockerfile
@@ -5,7 +5,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
   gcc-aarch64-linux-gnu qemu-user
 
 COPY install-musl.sh /
-RUN sh /install-musl.sh aarch64
+RUN /install-musl.sh aarch64
 
 # FIXME: shouldn't need the `-lgcc` here, shouldn't that be in std?
 ENV PATH=$PATH:/musl-aarch64/bin:/rust/bin \
diff --git a/ci/docker/arm-linux-androideabi/Dockerfile b/ci/docker/arm-linux-androideabi/Dockerfile
index 9d6a5c9649832..82f89f48e915c 100644
--- a/ci/docker/arm-linux-androideabi/Dockerfile
+++ b/ci/docker/arm-linux-androideabi/Dockerfile
@@ -20,8 +20,8 @@ COPY android* /android/
 ENV ANDROID_ARCH=arm
 ENV PATH=$PATH:/android/linux-x86_64/bin:/android/sdk/cmdline-tools/tools:/android/sdk/platform-tools
 
-RUN sh /android/android-install-ndk.sh
-RUN sh /android/android-install-sdk.sh $ANDROID_ARCH
+RUN /android/android-install-ndk.sh
+RUN /android/android-install-sdk.sh $ANDROID_ARCH
 RUN mv /root/.android /tmp
 RUN chmod 777 -R /tmp/.android
 RUN chmod 755 /android/sdk/cmdline-tools/tools/* /android/sdk/emulator/qemu/linux-x86_64/*
diff --git a/ci/docker/arm-unknown-linux-musleabihf/Dockerfile b/ci/docker/arm-unknown-linux-musleabihf/Dockerfile
index f8a5d27df3b5f..7ed23611c351e 100644
--- a/ci/docker/arm-unknown-linux-musleabihf/Dockerfile
+++ b/ci/docker/arm-unknown-linux-musleabihf/Dockerfile
@@ -8,7 +8,7 @@ RUN sed -i -E 's/(archive|security)\.ubuntu\.com/old-releases.ubuntu.com/g' \
         gcc-arm-linux-gnueabihf qemu-user
 
 COPY install-musl.sh /
-RUN sh /install-musl.sh arm
+RUN /install-musl.sh arm
 
 ENV PATH=$PATH:/musl-arm/bin:/rust/bin \
     CC_arm_unknown_linux_musleabihf=musl-gcc \
diff --git a/ci/docker/asmjs-unknown-emscripten/Dockerfile b/ci/docker/asmjs-unknown-emscripten/Dockerfile
index 6f2d5ddfc78e1..085e45ff35ee6 100644
--- a/ci/docker/asmjs-unknown-emscripten/Dockerfile
+++ b/ci/docker/asmjs-unknown-emscripten/Dockerfile
@@ -18,7 +18,7 @@ RUN apt-get install -y --no-install-recommends \
     bzip2
 
 COPY emscripten.sh /
-RUN bash /emscripten.sh
+RUN /emscripten.sh
 
 ENV PATH=$PATH:/rust/bin \
     CARGO_TARGET_ASMJS_UNKNOWN_EMSCRIPTEN_RUNNER=node
diff --git a/ci/docker/i686-linux-android/Dockerfile b/ci/docker/i686-linux-android/Dockerfile
index 0fb48aca342d4..8a159cd0502b5 100644
--- a/ci/docker/i686-linux-android/Dockerfile
+++ b/ci/docker/i686-linux-android/Dockerfile
@@ -20,8 +20,8 @@ COPY android* /android/
 ENV ANDROID_ARCH=i686
 ENV PATH=$PATH:/android/linux-x86_64/bin:/android/sdk/cmdline-tools/tools:/android/sdk/platform-tools
 
-RUN sh /android/android-install-ndk.sh
-RUN sh /android/android-install-sdk.sh $ANDROID_ARCH
+RUN /android/android-install-ndk.sh
+RUN /android/android-install-sdk.sh $ANDROID_ARCH
 RUN mv /root/.android /tmp
 RUN chmod 777 -R /tmp/.android
 RUN chmod 755 /android/sdk/cmdline-tools/tools/* /android/sdk/emulator/qemu/linux-x86_64/*
diff --git a/ci/docker/i686-unknown-linux-musl/Dockerfile b/ci/docker/i686-unknown-linux-musl/Dockerfile
index 4f36d2075485c..ea5e2e963910b 100644
--- a/ci/docker/i686-unknown-linux-musl/Dockerfile
+++ b/ci/docker/i686-unknown-linux-musl/Dockerfile
@@ -9,7 +9,7 @@ RUN sed -i -E 's/(archive|security)\.ubuntu\.com/old-releases.ubuntu.com/g' \
         gcc-multilib make libc6-dev git curl ca-certificates libc6-i386
 
 COPY install-musl.sh /
-RUN sh /install-musl.sh i686
+RUN /install-musl.sh i686
 
 ENV PATH=$PATH:/musl-i686/bin:/rust/bin \
     CC_i686_unknown_linux_musl=musl-gcc \
diff --git a/ci/docker/loongarch64-unknown-linux-musl/Dockerfile b/ci/docker/loongarch64-unknown-linux-musl/Dockerfile
index 2efd095b0fddd..f4a23a6666c8a 100644
--- a/ci/docker/loongarch64-unknown-linux-musl/Dockerfile
+++ b/ci/docker/loongarch64-unknown-linux-musl/Dockerfile
@@ -4,7 +4,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
         ca-certificates curl gcc git libc6-dev make qemu-user xz-utils
 
 COPY install-musl-cross.sh /
-RUN sh /install-musl-cross.sh loongarch64-unknown-linux-musl
+RUN /install-musl-cross.sh loongarch64-unknown-linux-musl
 
 ENV CARGO_TARGET_LOONGARCH64_UNKNOWN_LINUX_MUSL_LINKER=loongarch64-unknown-linux-musl-gcc \
     CARGO_TARGET_LOONGARCH64_UNKNOWN_LINUX_MUSL_RUNNER="qemu-loongarch64" \
diff --git a/ci/docker/s390x-unknown-linux-gnu/Dockerfile b/ci/docker/s390x-unknown-linux-gnu/Dockerfile
index 306d773a61165..dde2ef24254fc 100644
--- a/ci/docker/s390x-unknown-linux-gnu/Dockerfile
+++ b/ci/docker/s390x-unknown-linux-gnu/Dockerfile
@@ -8,7 +8,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
         cpio
 
 COPY linux-s390x.sh /
-RUN bash /linux-s390x.sh
+RUN /linux-s390x.sh
 
 COPY test-runner-linux /
 
diff --git a/ci/docker/s390x-unknown-linux-musl/Dockerfile b/ci/docker/s390x-unknown-linux-musl/Dockerfile
index d103a1d7488e0..4e202d1905902 100644
--- a/ci/docker/s390x-unknown-linux-musl/Dockerfile
+++ b/ci/docker/s390x-unknown-linux-musl/Dockerfile
@@ -7,7 +7,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
         qemu-user
 
 COPY install-musl.sh /
-RUN sh /install-musl.sh s390x
+RUN /install-musl.sh s390x
 
 # FIXME: shouldn't need the `-lgcc` here, shouldn't that be in std?
 ENV CARGO_TARGET_S390X_UNKNOWN_LINUX_GNU_LINKER=s390x-linux-gnu-gcc \
diff --git a/ci/docker/sparc64-unknown-linux-gnu/Dockerfile b/ci/docker/sparc64-unknown-linux-gnu/Dockerfile
index 4aff82ee46631..16b930f95a834 100644
--- a/ci/docker/sparc64-unknown-linux-gnu/Dockerfile
+++ b/ci/docker/sparc64-unknown-linux-gnu/Dockerfile
@@ -15,7 +15,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
         p7zip-full cpio linux-libc-dev-sparc64-cross
 
 COPY linux-sparc64.sh /
-RUN bash /linux-sparc64.sh
+RUN /linux-sparc64.sh
 
 COPY test-runner-linux /
 
diff --git a/ci/docker/wasm32-unknown-emscripten/Dockerfile b/ci/docker/wasm32-unknown-emscripten/Dockerfile
index 5af38ca5258db..0f9cb85dc30e8 100644
--- a/ci/docker/wasm32-unknown-emscripten/Dockerfile
+++ b/ci/docker/wasm32-unknown-emscripten/Dockerfile
@@ -26,7 +26,7 @@ RUN apt-get install -y --no-install-recommends \
 RUN ln -s /usr/bin/python3 /usr/bin/python & \
     ln -s /usr/bin/pip3 /usr/bin/pip
 COPY emscripten.sh /
-RUN bash /emscripten.sh
+RUN /emscripten.sh
 
 ENV PATH=$PATH:/rust/bin \
     CARGO_TARGET_WASM32_UNKNOWN_EMSCRIPTEN_RUNNER=node-wrapper.sh
diff --git a/ci/docker/wasm32-wasip1/Dockerfile b/ci/docker/wasm32-wasip1/Dockerfile
index 68940f4615a7e..e85b27ff82099 100644
--- a/ci/docker/wasm32-wasip1/Dockerfile
+++ b/ci/docker/wasm32-wasip1/Dockerfile
@@ -1,7 +1,7 @@
 FROM ubuntu:24.10
 
 COPY wasi.sh /
-RUN bash /wasi.sh
+RUN /wasi.sh
 
 # Note that `-D_WASI_EMULATED_PROCESS_CLOCKS` is used to enable access to
 # clock-related defines even though they're emulated. Also note that the usage
diff --git a/ci/docker/wasm32-wasip2/Dockerfile b/ci/docker/wasm32-wasip2/Dockerfile
index 7abaaf54da02d..be6bff3a843c5 100644
--- a/ci/docker/wasm32-wasip2/Dockerfile
+++ b/ci/docker/wasm32-wasip2/Dockerfile
@@ -1,7 +1,7 @@
 FROM ubuntu:24.10
 
 COPY wasi.sh /
-RUN bash /wasi.sh
+RUN /wasi.sh
 
 # Note that most of these are copied from `wasm32-wasip1/Dockerfile`
 #
diff --git a/ci/docker/x86_64-linux-android/Dockerfile b/ci/docker/x86_64-linux-android/Dockerfile
index f6331f10f3897..3bf350820019f 100644
--- a/ci/docker/x86_64-linux-android/Dockerfile
+++ b/ci/docker/x86_64-linux-android/Dockerfile
@@ -12,12 +12,12 @@ RUN apt-get update && \
 WORKDIR /android/
 ENV ANDROID_ARCH=x86_64
 COPY android-install-ndk.sh /android/
-RUN sh /android/android-install-ndk.sh
+RUN /android/android-install-ndk.sh
 
 # We do not run x86_64-linux-android tests on an android emulator.
 # See ci/android-sysimage.sh for information about how tests are run.
 COPY android-sysimage.sh /android/
-RUN bash /android/android-sysimage.sh x86_64 x86_64-24_r07.zip
+RUN /android/android-sysimage.sh x86_64 x86_64-24_r07.zip
 
 ENV PATH=$PATH:/rust/bin:/android/linux-x86_64/bin \
     CARGO_TARGET_X86_64_LINUX_ANDROID_LINKER=x86_64-linux-android28-clang \
diff --git a/ci/docker/x86_64-unknown-linux-musl/Dockerfile b/ci/docker/x86_64-unknown-linux-musl/Dockerfile
index 11fbd6e1be46a..d03df5b4f54ce 100644
--- a/ci/docker/x86_64-unknown-linux-musl/Dockerfile
+++ b/ci/docker/x86_64-unknown-linux-musl/Dockerfile
@@ -5,7 +5,7 @@ RUN apt-get install -y --no-install-recommends \
   gcc make libc6-dev git curl ca-certificates
 
 COPY install-musl.sh /
-RUN sh /install-musl.sh x86_64
+RUN /install-musl.sh x86_64
 
 ENV PATH=$PATH:/musl-x86_64/bin:/rust/bin \
     RUSTFLAGS="-L /musl-x86_64/lib"
diff --git a/ci/emscripten.sh b/ci/emscripten.sh
old mode 100644
new mode 100755
diff --git a/ci/install-musl-cross.sh b/ci/install-musl-cross.sh
old mode 100644
new mode 100755
diff --git a/ci/install-musl.sh b/ci/install-musl.sh
old mode 100644
new mode 100755
diff --git a/ci/install-rust.sh b/ci/install-rust.sh
old mode 100644
new mode 100755
index becb532d1469d..16fd0b4e8a577
--- a/ci/install-rust.sh
+++ b/ci/install-rust.sh
@@ -8,17 +8,25 @@ echo "Setup toolchain"
 toolchain="${TOOLCHAIN:-nightly}"
 os="${OS:-}"
 
-if [ "$os" = "windows" ]; then
-    : "${TARGET?The TARGET environment variable must be set.}"
-    rustup set profile minimal
-    rustup update --force "$toolchain-$TARGET"
-    rustup default "$toolchain-$TARGET"
-else
+case "$(uname -s)" in
+    Linux*)     os=linux ;;
+    Darwin*)    os=macos ;;
+    MINGW*)     os=windows ;;
+    *)
+        echo "Unknown system $(uname -s)"
+        exit 1
+        ;;
+esac
+
+if [ "$os" = "windows" ] && [ -n "${TARGET:-}" ]; then
+    toolchain="$toolchain-$TARGET"
     rustup set profile minimal
-    rustup update --force "$toolchain"
-    rustup default "$toolchain"
 fi
 
+rustup set profile minimal
+rustup update --force "$toolchain"
+rustup default "$toolchain"
+
 if [ -n "${TARGET:-}" ]; then
     echo "Install target"
     rustup target add "$TARGET"
@@ -50,9 +58,6 @@ if [ "$os" = "windows" ]; then
 fi
 
 echo "Query rust and cargo versions"
-command -v rustc
-command -v cargo
-command -v rustup
 rustc -Vv
 cargo -V
 rustup -Vv
diff --git a/ci/linux-s390x.sh b/ci/linux-s390x.sh
old mode 100644
new mode 100755
diff --git a/ci/linux-sparc64.sh b/ci/linux-sparc64.sh
old mode 100644
new mode 100755
diff --git a/ci/run-docker.sh b/ci/run-docker.sh
index 4cef3d45c504d..fcd9e1a9d2e03 100755
--- a/ci/run-docker.sh
+++ b/ci/run-docker.sh
@@ -8,6 +8,8 @@
 
 set -eux
 
+target="$1"
+
 # Default to assuming the CARGO_HOME is one directory up (to account for a `bin`
 # subdir) from where the `cargo` binary in `$PATH` lives.
 default_cargo_home="$(dirname "$(dirname "$(command -v cargo)")")"
@@ -18,17 +20,17 @@ export CARGO_HOME="${CARGO_HOME:-$default_cargo_home}"
 echo "${HOME}"
 pwd
 
-# Avoid "no space left on device" failure.
-if [ "${1}" = "aarch64-linux-android" ] ; then
+# Avoid "no space left on device" failure if running in CI
+if [ "${CI:-0}" != "0" ] && [ "$target" = "aarch64-linux-android" ] ; then
     docker system prune -af
     docker system df
 fi
 
 run() {
-    echo "Building docker container for target ${1}"
+    echo "Building docker container for target $target"
 
     # use -f so we can use ci/ as build context
-    docker build -t "libc-${1}" -f "ci/docker/${1}/Dockerfile" ci/
+    docker build -t "libc-$target" -f "ci/docker/$target/Dockerfile" ci/
     mkdir -p target
     if [ -w /dev/kvm ]; then
         kvm="--volume /dev/kvm:/dev/kvm"
@@ -50,8 +52,8 @@ run() {
         $kvm \
         --init \
         --workdir /checkout \
-        "libc-${1}" \
-        sh -c "HOME=/tmp PATH=\$PATH:/rust/bin exec ci/run.sh ${1}"
+        "libc-$target" \
+        sh -c "HOME=/tmp PATH=\$PATH:/rust/bin exec ci/run.sh $target"
 }
 
 build_switch() {
@@ -88,13 +90,13 @@ build_switch() {
             && cargo build -Z build-std=core,alloc --target ci/switch.json"
 }
 
-if [ -z "${1}" ]; then
+if [ -z "$target" ]; then
     for d in ci/docker/*; do
         run "${d}"
     done
 else
-    if [ "${1}" != "switch" ]; then
-        run "${1}"
+    if [ "$target" != "switch" ]; then
+        run "$target"
     else
         build_switch
     fi
diff --git a/ci/run.sh b/ci/run.sh
index f4fef82fcdc2d..22b356a6425b1 100755
--- a/ci/run.sh
+++ b/ci/run.sh
@@ -21,25 +21,21 @@ if [ -n "${QEMU:-}" ]; then
 
     if [ -z "${QEMU#*.gz}" ]; then
         # image is .gz : download and uncompress it
-        qemufile="$(echo "${QEMU%.gz}" | sed 's/\//__/g')"
-        if [ ! -f "${tmpdir}/${qemufile}" ]; then
-            curl --retry 5 "${mirrors_url}/${QEMU}" |
-                gunzip -d > "${tmpdir}/${qemufile}"
-        fi
+        base_file="${QEMU%.gz}"
+        pipe_cmd="gunzip -d"
     elif [ -z "${QEMU#*.xz}" ]; then
         # image is .xz : download and uncompress it
-        qemufile="$(echo "${QEMU%.xz}" | sed 's/\//__/g')"
-        if [ ! -f "${tmpdir}/${qemufile}" ]; then
-            curl --retry 5 "${mirrors_url}/${QEMU}" |
-                unxz > "${tmpdir}/${qemufile}"
-        fi
+        base_file="${QEMU%.xz}"
+        pipe_cmd="unxz"
     else
         # plain qcow2 image: just download it
-        qemufile="$(echo "${QEMU}" | sed 's/\//__/g')"
-        if [ ! -f "${tmpdir}/${qemufile}" ]; then
-            curl --retry 5 "${mirrors_url}/${QEMU}" \
-                > "${tmpdir}/${qemufile}"
-        fi
+        base_file="$QEMU"
+        pipe_cmd="cat" # nop to forward the result
+    fi
+
+    qemufile="$(echo "$base_file" | sed 's/\//__/g')"
+    if [ ! -f "${tmpdir}/${qemufile}" ]; then
+        curl --retry 5 "${mirrors_url}/${QEMU}" | $pipe_cmd > "${tmpdir}/${qemufile}"
     fi
 
     # Create a mount a fresh new filesystem image that we'll later pass to QEMU.
diff --git a/ci/style.rs b/ci/style.rs
index dbc8c633cffab..c4e0fb0db8058 100644
--- a/ci/style.rs
+++ b/ci/style.rs
@@ -100,7 +100,7 @@ fn check_style(file: &str, path: &Path, err: &mut Errors) {
 
     // FIXME: see below
     // let mut s_macros = 0;
-    
+
     let mut f_macros = 0;
     let mut in_impl = false;
 
diff --git a/ci/style.sh b/ci/style.sh
index 17a47d037360a..c758712012e16 100755
--- a/ci/style.sh
+++ b/ci/style.sh
@@ -75,7 +75,7 @@ fi
 export LC_ALL=C
 
 for file in libc-test/semver/*.txt; do
-    case "$file" in 
+    case "$file" in
       *TODO*) continue ;;
     esac
 
diff --git a/ci/build.sh b/ci/verify-build.sh
old mode 100644
new mode 100755
similarity index 57%
rename from ci/build.sh
rename to ci/verify-build.sh
index f9c81beb19672..b88e214fb34d1
--- a/ci/build.sh
+++ b/ci/verify-build.sh
@@ -8,24 +8,45 @@
 set -eux
 
 : "${TOOLCHAIN?The TOOLCHAIN environment variable must be set.}"
-: "${OS?The OS environment variable must be set.}"
 
 rust="$TOOLCHAIN"
 filter="${FILTER:-}"
 
-echo "Testing Rust $rust on $OS"
+case "$(uname -s)" in
+    Linux*)     os=linux ;;
+    Darwin*)    os=macos ;;
+    MINGW*)     os=windows ;;
+    *)
+        echo "Unknown system $(uname -s)"
+        exit 1
+        ;;
+esac
+
+echo "Testing Rust $rust on $os"
 
 if [ "$TOOLCHAIN" = "nightly" ] ; then
     rustup component add rust-src
 fi
 
 test_target() {
-    build_cmd="${1}"
-    target="${2}"
-    no_std="${3:-}"
+    target="${1}"
+    no_dist="${2:-0}"
+
+    RUSTFLAGS="${RUSTFLAGS:-}"
+
+    # The basic command that is run each time
+    cmd="cargo +$rust build --target $target"
+
+    if [ "${no_dist}" != "0" ]; then
+        # If we can't download a `core`, we need to build it
+        cmd="$cmd -Zbuild-std=core,alloc"
+
+        # FIXME: With `build-std` feature, `compiler_builtins` emits a lof of lint warnings.
+        RUSTFLAGS="${RUSTFLAGS:-} -Aimproper_ctypes_definitions"
+        export RUSTFLAGS
+    else
+        # Otherwise it is available for download; fetch it:
 
-    # If there is a std component, fetch it:
-    if [ "${no_std}" != "1" ]; then
         # FIXME: rustup often fails to download some artifacts due to network
         # issues, so we retry this N times.
         N=5
@@ -39,73 +60,14 @@ test_target() {
         done
     fi
 
-    # Test that libc builds without any default features (no std)
-    if [ "$no_std" != "1" ]; then
-        cargo "+$rust" "$build_cmd" --no-default-features --target "$target"
-    else
-        # FIXME: With `build-std` feature, `compiler_builtins` emits a lof of lint warnings.
-        RUSTFLAGS="-A improper_ctypes_definitions" \
-            cargo "+$rust" "$build_cmd" \
-            -Z build-std=core,alloc \
-            --no-default-features \
-            --target "$target"
-    fi
-
-    # Test that libc builds with default features (e.g. std)
-    # if the target supports std
-    if [ "$no_std" != "1" ]; then
-        cargo "+$rust" "$build_cmd" --target "$target"
-    else
-        RUSTFLAGS="-A improper_ctypes_definitions" \
-            cargo "+$rust" "${build_cmd}" \
-            -Z build-std=core,alloc \
-            --target "$target"
-    fi
-
-    # Test that libc builds with the `extra_traits` feature
-    if [ "$no_std" != "1" ]; then
-        cargo "+$rust" "$build_cmd" \
-            --no-default-features \
-            --features extra_traits \
-            --target "$target"
-    else
-        RUSTFLAGS="-A improper_ctypes_definitions" \
-            cargo "+$rust" "$build_cmd" \
-            -Z build-std=core,alloc \
-            --no-default-features \
-            --features extra_traits \
-            --target "$target"
-    fi
-
-    # Test the 'const-extern-fn' feature on nightly
-    if [ "${rust}" = "nightly" ]; then
-        if [ "${no_std}" != "1" ]; then
-            cargo "+$rust" "$build_cmd" \
-                --no-default-features \
-                --features const-extern-fn \
-                --target "$target"
-        else
-            RUSTFLAGS="-A improper_ctypes_definitions" \
-                cargo "+$rust" "$build_cmd" \
-                -Z build-std=core,alloc \
-                --no-default-features \
-                --features const-extern-fn \
-                --target "$target"
-        fi
-    fi
+    # Test with expected combinations of features
+    $cmd
+    $cmd --features const-extern-fn
+    $cmd --features extra_traits
 
-    # Also test that it builds with `extra_traits` and default features:
-    if [ "$no_std" != "1" ]; then
-        cargo "+$rust" "$build_cmd" \
-            --target "$target" \
-            --features extra_traits
-    else
-        RUSTFLAGS="-A improper_ctypes_definitions" \
-            cargo "+$rust" "$build_cmd" \
-            -Z build-std=core,alloc \
-            --target "$target" \
-            --features extra_traits
-    fi
+    # Test again without default features, i.e. without "std"
+    $cmd --no-default-features
+    $cmd --no-default-features --features extra_traits
 }
 
 rust_linux_targets="\
@@ -171,48 +133,10 @@ x86_64-pc-windows-gnu \
 i686-pc-windows-msvc \
 "
 
-# The targets are listed here alphabetically
-targets=""
-case "${OS}" in
-    linux*)
-        targets="$rust_linux_targets"
-
-        if [ "$rust" = "nightly" ]; then
-            targets="$targets $rust_nightly_linux_targets"
-        fi
-
-        ;;
-    macos*)
-        targets="$rust_apple_targets"
-
-        if [ "$rust" = "nightly" ]; then
-            targets="$targets $rust_nightly_apple_targets"
-        fi
-
-        ;;
-    windows*)
-        targets=${rust_nightly_windows_targets}
-        ;;
-    *) ;;
-esac
-
-for target in $targets; do
-    if echo "$target" | grep -q "$filter"; then
-        if [ "${OS}" = "windows" ]; then
-            TARGET="$target" sh ./ci/install-rust.sh
-            test_target build "$target"
-        else
-            test_target build "$target"
-        fi
-
-        test_run=1
-    fi
-done
-
 # Targets which are not available via rustup and must be built with -Zbuild-std
 # FIXME(hexagon): hexagon-unknown-linux-musl should be tested but currently has
 # duplicate symbol errors from `compiler_builtins`.
-rust_linux_no_core_targets="\
+rust_linux_no_dist_targets="\
 aarch64-pc-windows-msvc \
 aarch64-unknown-freebsd \
 aarch64-unknown-hermit \
@@ -276,31 +200,59 @@ x86_64-unknown-openbsd \
 x86_64-wrs-vxworks \
 "
 
-if [ "${rust}" = "nightly" ] && [ "${OS}" = "linux" ]; then
-    for target in $rust_linux_no_core_targets; do
-        if echo "$target" | grep -q "$FILTER"; then
-            test_target "$target" 1
-        fi
-
-        test_run=1
-    done
-fi
-
-rust_apple_no_core_targets="\
+rust_apple_no_dist_targets="\
 armv7s-apple-ios \
 i686-apple-darwin \
 i386-apple-ios \
 "
 
-if [ "${rust}" = "nightly" ] && [ "${OS}" = "macos" ]; then
-    for target in $rust_apple_no_core_targets; do
-        if echo "$target" | grep -q "$FILTER"; then
+# The targets are listed here alphabetically
+if [ "$os" = "linux" ]; then
+    targets="$rust_linux_targets"
+    nightly_targets="$rust_nightly_linux_targets"
+    no_dist_targets="$rust_linux_no_dist_targets"
+elif [ "$os" = "macos" ]; then
+    targets="$rust_apple_targets"
+    nightly_targets="$rust_nightly_apple_targets"
+    no_dist_targets="$rust_apple_no_dist_targets"
+elif [ "$os" = "windows" ]; then
+    targets=${rust_nightly_windows_targets}
+else
+    exit 1
+fi
+
+if [ "$rust" = "nightly" ]; then
+    targets="$targets ${nightly_targets:-}"
+else
+    # build-std requires nightly
+    no_dist_targets=""
+fi
+
+for target in $targets; do
+    if echo "$target" | grep -q "$filter"; then
+        if [ "$os" = "windows" ]; then
+            TARGET="$target" ./ci/install-rust.sh
+            test_target "$target"
+        else
+            test_target "$target"
+        fi
+
+        test_run=1
+    fi
+done
+
+for target in ${no_dist_targets:-}; do
+    if echo "$target" | grep -q "$filter"; then
+        if [ "$os" = "windows" ]; then
+            TARGET="$target" ./ci/install-rust.sh
+            test_target "$target" 1
+        else
             test_target "$target" 1
         fi
 
         test_run=1
-    done
-fi
+    fi
+done
 
 # Make sure we didn't accidentally filter everything
 if [ "${test_run:-}" != 1 ]; then
diff --git a/ci/wasi.sh b/ci/wasi.sh
old mode 100644
new mode 100755