diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7e0dccaf3..b1cace8f4 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -32,19 +32,20 @@ set(CMAKE_MODULE_PATH
   "${CMAKE_CURRENT_SOURCE_DIR}/cmake/modules"
   )
 
+# Define clad supported version of clang and llvm.
+set(CLANG_MIN_SUPPORTED 8.0)
+set(CLANG_MAX_SUPPORTED "18.1.x")
+set(CLANG_VERSION_UPPER_BOUND 18.2.0)
+set(LLVM_MIN_SUPPORTED 8.0)
+set(LLVM_MAX_SUPPORTED "18.1.x")
+set(LLVM_VERSION_UPPER_BOUND 18.2.0)
+
 # If we are not building as a part of LLVM, build clad as an
 # standalone project, using LLVM as an external library:
 if( CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR )
-  project(clad)
-
-  ## Define clad supported version of clang and llvm
+  set(CLAD_BUILT_STANDALONE 1)
 
-  set(CLANG_MIN_SUPPORTED 8.0)
-  set(CLANG_MAX_SUPPORTED "18.1.x")
-  set(CLANG_VERSION_UPPER_BOUND 18.2.0)
-  set(LLVM_MIN_SUPPORTED 8.0)
-  set(LLVM_MAX_SUPPORTED "18.1.x")
-  set(LLVM_VERSION_UPPER_BOUND 18.2.0)
+  project(clad)
 
   if (NOT DEFINED Clang_DIR)
     set(Clang_DIR ${LLVM_DIR})
@@ -134,26 +135,21 @@ if( CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR )
     message(FATAL_ERROR "Please set Clang_DIR pointing to the clang build or installation folder")
   endif()
 
-  set(CLANG_VERSION_MAJOR ${LLVM_VERSION_MAJOR})
-  set(CLANG_VERSION_MINOR ${LLVM_VERSION_MINOR})
-  set(CLANG_VERSION_PATCH ${LLVM_VERSION_PATCH})
-  set(CLANG_PACKAGE_VERSION ${LLVM_PACKAGE_VERSION})
-
-  if (CLANG_PACKAGE_VERSION VERSION_LESS CLANG_MIN_SUPPORTED OR CLANG_PACKAGE_VERSION VERSION_GREATER_EQUAL CLANG_VERSION_UPPER_BOUND)
-    message(FATAL_ERROR "Found unsupported version: Clang ${CLANG_PACKAGE_VERSION};\nPlease set Clang_DIR pointing to the clang version ${CLANG_MIN_SUPPORTED} to ${CLANG_MAX_SUPPORTED} build or installation folder")
+  if (LLVM_PACKAGE_VERSION VERSION_LESS CLANG_MIN_SUPPORTED OR LLVM_PACKAGE_VERSION VERSION_GREATER_EQUAL CLANG_VERSION_UPPER_BOUND)
+    message(FATAL_ERROR "Found unsupported version: Clang ${LLVM_PACKAGE_VERSION};\nPlease set Clang_DIR pointing to the clang version ${CLANG_MIN_SUPPORTED} to ${CLANG_MAX_SUPPORTED} build or installation folder")
   endif()
 
-  message(STATUS "Found supported version: Clang ${CLANG_PACKAGE_VERSION}")
+  message(STATUS "Found supported version: Clang ${LLVM_PACKAGE_VERSION}")
   message(STATUS "Using ClangConfig.cmake in: ${Clang_DIR}")
 
-  if (CLANG_VERSION_MAJOR GREATER_EQUAL 16)
+  if (LLVM_VERSION_MAJOR GREATER_EQUAL 16)
     if (NOT CMAKE_CXX_STANDARD)
       set (CMAKE_CXX_STANDARD 17)
     endif()
     if (CMAKE_CXX_STANDARD LESS 17)
       message(fatal "LLVM/Clad requires C++17 or later")
     endif()
-  elseif (CLANG_VERSION_MAJOR GREATER_EQUAL 10)
+  elseif (LLVM_VERSION_MAJOR GREATER_EQUAL 10)
     if (NOT CMAKE_CXX_STANDARD)
       set (CMAKE_CXX_STANDARD 14)
     endif()
@@ -179,35 +175,11 @@ if( CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR )
 
   set(CMAKE_INCLUDE_CURRENT_DIR ON)
 
-  # In rare cases we might want to have clang installed in a different place
-  # than llvm and the header files should be found first (even though the
-  # LLVM_INCLUDE_DIRS) contain clang headers, too.
-  include_directories(SYSTEM ${CLANG_INCLUDE_DIRS})
-  include_directories(SYSTEM ${LLVM_INCLUDE_DIRS})
   add_definitions(${LLVM_DEFINITIONS})
 
-  # If the llvm sources are present add them with higher priority.
-  if (LLVM_BUILD_MAIN_SRC_DIR)
-    # LLVM_INCLUDE_DIRS contains the include paths to both LLVM's source and
-    # build directories. Since we cannot just include ClangConfig.cmake (see
-    # fixme above) we have to do a little more work to get the right include
-    # paths for clang.
-    #
-    # FIXME: We only support in-tree builds of clang, that is clang being built
-    # in llvm_src/tools/clang.
-    include_directories(SYSTEM ${LLVM_BUILD_MAIN_SRC_DIR}/tools/clang/include/)
-
-    if (NOT LLVM_BUILD_BINARY_DIR)
-      message(FATAL "LLVM_BUILD_* values should be available for the build tree")
-    endif()
-
-    include_directories(SYSTEM ${LLVM_BUILD_BINARY_DIR}/tools/clang/include/)
-  endif()
-
   set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib/)
   set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin/)
 
-  set( CLAD_BUILT_STANDALONE 1 )
 else()
   # Not standalone; we are building within llvm
   if (NOT "clang" IN_LIST LLVM_ENABLE_PROJECTS)
@@ -216,24 +188,14 @@ else()
 
   message(STATUS "Building Clad as part of LLVM")
 
-  # Try finding the LLVMConfig.cmake if we build against prebuilt LLVM
-  set(LLVM_CMAKE_PATH "${LLVM_BINARY_DIR}/lib${LLVM_LIBDIR_SUFFIX}/cmake/llvm")
-  set(LLVMCONFIG_FILE "${LLVM_CMAKE_PATH}/LLVMConfig.cmake")
-  if(EXISTS ${LLVMCONFIG_FILE})
-    list(APPEND CMAKE_MODULE_PATH "${LLVM_CMAKE_PATH}")
-    include(${LLVMCONFIG_FILE})
+  if (PACKAGE_VERSION VERSION_LESS CLANG_MIN_SUPPORTED OR PACKAGE_VERSION VERSION_GREATER_EQUAL CLANG_VERSION_UPPER_BOUND)
+    message(WARNING "Building against unsupported version: Clang ${PACKAGE_VERSION};\n Supported versions are from ${CLANG_MIN_SUPPORTED} to ${CLANG_MAX_SUPPORTED}.")
   endif()
 
+  set(CLANG_SOURCE_DIR ${LLVM_SOURCE_DIR}/../clang)
+  set(CLANG_BINARY_DIR ${LLVM_TOOLS_BINARY_DIR}/clang)
   if (NOT CLANG_INCLUDE_DIRS)
-    set (CLANG_INCLUDE_DIRS "${LLVM_MAIN_SRC_DIR}/tools/clang/include")
-    if (NOT EXISTS ${CLANG_INCLUDE_DIRS})
-      # Otherwise assume the monorepo layout.
-      set (CLANG_INCLUDE_DIRS ${LLVM_MAIN_SRC_DIR}/../clang/include )
-    endif()
-    set (CLANG_INCLUDE_DIRS "${CLANG_INCLUDE_DIRS}" "${LLVM_BINARY_DIR}/tools/clang/include")
-  endif()
-  if (NOT LLVM_INCLUDE_DIRS)
-    set (LLVM_INCLUDE_DIRS "${LLVM_MAIN_SRC_DIR}/include" "${LLVM_BINARY_DIR}/include")
+    set(CLANG_INCLUDE_DIRS "${CLANG_SOURCE_DIR}/include" "${CLANG_BINARY_DIR}/include")
   endif()
 endif()
 
diff --git a/Compatibility.cmake b/Compatibility.cmake
index de69699ea..b5dae29f5 100644
--- a/Compatibility.cmake
+++ b/Compatibility.cmake
@@ -19,7 +19,7 @@ if (NOT COMMAND add_version_info_from_vcs)
 # find_first_existing_vc_file(var path) --> find_first_existing_vc_file(path var)
   macro(clad_compat__find_first_existing_vc_file path out_var)
     if (COMMAND find_first_existing_vc_file)
-      find_first_existing_vc_file(${path} out_var)
+      find_first_existing_vc_file("${path}" out_var)
     endif()
   endmacro(clad_compat__find_first_existing_vc_file)
 else()
@@ -27,7 +27,7 @@ else()
 # find_first_existing_vc_file(var path) --> find_first_existing_vc_file(path var)
   macro(clad_compat__find_first_existing_vc_file path out_var)
     if (COMMAND find_first_existing_vc_file)
-      find_first_existing_vc_file(out_var ${path})
+      find_first_existing_vc_file(out_var "${path}")
     endif()
   endmacro(clad_compat__find_first_existing_vc_file)
 endif()
diff --git a/README.md b/README.md
index bfae57d9b..52926cde7 100644
--- a/README.md
+++ b/README.md
@@ -280,25 +280,17 @@ Clone the LLVM project and checkout the required LLVM version (Currently support
 
 ```
 git clone https://github.com/llvm/llvm-project.git
+git clone https://github.com/vgvassilev/clad.git
 cd llvm-project
-git checkout llvmorg-16.0.0
-```
-Build Clang:
-```
-mkdir build && cd build
-cmake -DLLVM_ENABLE_PROJECTS="clang" -DCMAKE_BUILD_TYPE="DEBUG" -DLLVM_TARGETS_TO_BUILD=host -DLLVM_INSTALL_UTILS=ON ../llvm
-cmake --build . --target clang --parallel $(nproc --all)
-make -j8 check-clang # this installs llvm-config required by lit
-cd ../..
+git checkout llvmorg-18.0.0
 ```
 
-Clone and build Clad:
+Build Clad with Clang and LLVM:
 ```
-git clone https://github.com/vgvassilev/clad.git
-cd clad
 mkdir build && cd build
-cmake -DLLVM_DIR=PATH/TO/llvm-project/build -DCMAKE_BUILD_TYPE=DEBUG -DLLVM_EXTERNAL_LIT="$(which lit)" ../
-make -j8 clad
+cmake -DLLVM_ENABLE_PROJECTS="clang" -DLLVM_EXTERNAL_PROJECTS=clad -DLLVM_EXTERNAL_CLAD_SOURCE_DIR=../../clad -DCMAKE_BUILD_TYPE="Debug" -DLLVM_TARGETS_TO_BUILD=host -DLLVM_INSTALL_UTILS=ON ../llvm
+cmake --build . --target clad --parallel $(nproc --all)
+cd ../..
 ```
 
 Run the Clad tests:
diff --git a/lib/Differentiator/CMakeLists.txt b/lib/Differentiator/CMakeLists.txt
index 177608449..22e293ca5 100644
--- a/lib/Differentiator/CMakeLists.txt
+++ b/lib/Differentiator/CMakeLists.txt
@@ -1,8 +1,3 @@
-set(CLANG_SOURCE_DIR ${CLAD_SOURCE_DIR}/../clang/)
-if (NOT EXISTS ${CLANG_SOURCE_DIR})
-  set(CLANG_SOURCE_DIR "${Clang_DIR}/")
-endif()
-
 clad_compat__find_first_existing_vc_file("${CLANG_SOURCE_DIR}" clang_vc)
 clad_compat__find_first_existing_vc_file("${CLAD_SOURCE_DIR}" clad_vc)
 
diff --git a/test/lit.site.cfg.in b/test/lit.site.cfg.in
index b1eccea24..d40f514ab 100644
--- a/test/lit.site.cfg.in
+++ b/test/lit.site.cfg.in
@@ -3,7 +3,7 @@ import sys
 ## Autogenerated by LLVM/clad configuration.
 # Do not edit!
 llvm_version_major = @LLVM_VERSION_MAJOR@
-config.clang_version_major = @CLANG_VERSION_MAJOR@
+config.clang_version_major = @LLVM_VERSION_MAJOR@
 config.llvm_src_root = "@LLVM_SOURCE_DIR@"
 config.llvm_obj_root = "@LLVM_BINARY_DIR@"
 config.llvm_tools_dir = "@LLVM_TOOLS_DIR@"
diff --git a/tools/CMakeLists.txt b/tools/CMakeLists.txt
index b5884863d..ecf61f4ae 100644
--- a/tools/CMakeLists.txt
+++ b/tools/CMakeLists.txt
@@ -82,7 +82,7 @@ if (NOT CLAD_BUILD_STATIC_ONLY)
       )
 
     # Set build byproducts only needed by Ninja.
-    set(_enzyme_static_target EnzymeStatic-${CLANG_VERSION_MAJOR})
+    set(_enzyme_static_target EnzymeStatic-${LLVM_VERSION_MAJOR})
     set(_enzyme_static_archive_name ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}${CMAKE_STATIC_LIBRARY_PREFIX}${_enzyme_static_target}${CMAKE_STATIC_LIBRARY_SUFFIX})
     if("${CMAKE_GENERATOR}" STREQUAL "Ninja")
       set(ENZYME_BYPRODUCTS ${_enzyme_static_archive_name})
@@ -134,4 +134,4 @@ if (NOT CLAD_BUILD_STATIC_ONLY)
     add_dependencies(clad LLVMEnzyme)
   endif(CLAD_ENABLE_ENZYME_BACKEND)
 endif()
-set_source_files_properties(ClangPlugin.cpp PROPERTIES COMPILE_DEFINITIONS CLANG_MAJOR_VERSION="${CLANG_VERSION_MAJOR}")
+set_source_files_properties(ClangPlugin.cpp PROPERTIES COMPILE_DEFINITIONS CLANG_MAJOR_VERSION="${LLVM_VERSION_MAJOR}")
diff --git a/unittests/CMakeLists.txt b/unittests/CMakeLists.txt
index c714bee97..db528990c 100644
--- a/unittests/CMakeLists.txt
+++ b/unittests/CMakeLists.txt
@@ -4,6 +4,9 @@ set_target_properties(CladUnitTests PROPERTIES FOLDER "Clad tests")
 # LLVM builds (not installed llvm) provides gtest.
 if (NOT TARGET gtest)
   include(CladGoogleTest)
+  if(NOT CLAD_BUILT_STANDALONE)
+    add_dependencies(googletest clang)
+  endif()
 endif()
 
 # add_clad_unittest(test_dirname file1.cpp file2.cpp)