Testing cross-compile action

Author: andrjohns

.github/workflows/cross_test.yml

@@ -0,0 +1,47 @@
+name: Win ARM64 Cross-Compile  Tests
+
+on:
+  push:
+    branches:
+      - cross-tests
+
+jobs:
+  build:
+    runs-on: windows-latest
+    env:
+      MINGW64_PREFIX: "C:/msys64/clang64"
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: download Rtools-aarch64
+        run: |
+          curl https://www.r-project.org/nosvn/winutf8/ucrt3/llvm19_ucrt3_full_aarch64_6536.tar.zst -o llvm-aarch64.tar.zst
+          tar -xf llvm-aarch64.tar.zst
+
+      - uses: msys2/setup-msys2@v2
+        if: always()
+        with:
+          location: C:/
+          msystem: CLANG64
+          install:
+            mingw-w64-clang-x86_64-clang
+
+      - name: Copy clang rt libs
+        if: always()
+        run: |
+          cp aarch64-w64-mingw32.static.posix/lib/clang/19/lib/windows/libclang_rt.builtins-aarch64.a ${{env.MINGW64_PREFIX}}/lib/clang/19/lib/windows/
+        shell: bash
+          
+      - name: Setup make/local
+        if: always()
+        run: |
+          touch make/local
+          echo "CXX=clang++ --target=aarch64-w64-mingw32 --sysroot='$(pwd)/aarch64-w64-mingw32.static.posix'" >> make/local
+          echo "CC=clang --target=aarch64-w64-mingw32 --sysroot='$(pwd)/aarch64-w64-mingw32.static.posix'" >> make/local
+        shell: bash
+
+      - name: Build Math libs
+        shell: bash
+        run: |
+          make -f make/standalone math-libs -j2
+