initial pass at arm cross compile

.github/workflows/build_python.yml

@@ -24,7 +24,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        arch: [ x86_64, aarch64 ]
+        arch: [ x86_64, aarch64, arm ]
 
     steps:
       - name: Checkout

scripts/qemu_arm_interpreter

@@ -0,0 +1,14 @@
+#!/bin/bash
+# this interpreter shim is used by cmake to run platform
+# detection programs
+
+# we need to ensure that the binary uses the correct libc
+# so first patch the program
+patchelf --add-rpath /usr/arm-linux-gnueabihf/lib/ $1
+patchelf --add-needed libm.so.6 $1
+patchelf --add-needed libpthread.so.0 $1
+patchelf --add-needed libdl.so.2 $1
+patchelf --add-needed libutil.so.1 $1
+
+# run the interpreter
+qemu-arm-static "$@"