fixup! .github/workflows/ci.yml: test Windows on ARM.

Author: dot-asm

.github/workflows/ci.yml

@@ -169,7 +169,10 @@ jobs:
       shell: bash
       run: |
         go version 2>/dev/null || exit 0
-        if ! (grep -q -e '^flags.*\badx\b' /proc/cpuinfo) 2>/dev/null; then
+        if [ $OSTYPE = "msys" -a $RUNNER_ARCH = "ARM64" ]; then
+            export CC=clang
+            export CGO_CFLAGS="-O --target=aarch64-pc-windows-msvc"
+        elif ! (grep -q -e '^flags.*\badx\b' /proc/cpuinfo) 2>/dev/null; then
             export CGO_CFLAGS="-O -D__BLST_PORTABLE__"
         fi
         cd bindings/go