Add support for CLANGARM64 target

Signed-off-by: Dennis Ameling <dennis@dennisameling.com>

Author: dennisameling

.github/workflows/clang-build.yml

@@ -0,0 +1,37 @@
+name: CLANG build
+
+on:
+  workflow_dispatch:
+
+defaults:
+  run:
+    shell: bash
+
+jobs:
+  clang-build:
+    runs-on: [Windows, ARM64]
+    env:
+      NO_PERL: 1
+    steps:
+      - uses: actions/checkout@v3
+      - uses: dennisameling/setup-git-for-windows-sdk@01872063f7b133eae0732176f08e309a69c22b4d
+        with:
+          flavor: full
+          architecture: aarch64
+      - name: Add clangarm64 server
+        run: |
+          cat <<EOF >> /etc/pacman.conf
+          [clangarm64]
+          Server = https://mirror.msys2.org/mingw/clangarm64/
+          EOF
+          pacman -Sy
+      - name: Install packages
+        # The clangarm64 folder is missing in the Git for Windows SDK, so let's create it
+        run: |
+          mkdir -p /clangarm64
+          pacman -S --noconfirm base-devel mingw-w64-clang-aarch64-openssl mingw-w64-clang-aarch64-zlib \
+          mingw-w64-clang-aarch64-curl mingw-w64-clang-aarch64-expat \
+          mingw-w64-clang-aarch64-libiconv mingw-w64-clang-aarch64-toolchain \
+          mingw-w64-clang-aarch64-pcre2 mingw-w64-clang-aarch64-libssp
+      - name: Build Git CLANGARM64
+        run: make -j`nproc`

compat/bswap.h

@@ -74,6 +74,12 @@ static inline uint64_t git_bswap64(uint64_t x)
 }
 #endif
 
+/* available since Clang 12 and GCC 10, i.a. needed for ARM64/aarch64 on Windows */
+#elif defined(__has_builtin) && __has_builtin(__builtin_bswap64)
+
+#define bswap32(x)     __builtin_bswap32((x))
+#define bswap64(x)     __builtin_bswap64((x))
+
 #elif defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_X64) || defined(_M_ARM64))
 
 #include <stdlib.h>

config.mak.uname

@@ -711,6 +711,10 @@ else
 			prefix = /mingw64
 			HOST_CPU = x86_64
 			BASIC_LDFLAGS += -Wl,--pic-executable,-e,mainCRTStartup
+		else ifeq (CLANGARM64,$(MSYSTEM))
+			prefix = /clangarm64
+			HOST_CPU = aarch64
+			BASIC_LDFLAGS += -Wl,--pic-executable,-e,mainCRTStartup
 		else
 			COMPAT_CFLAGS += -D_USE_32BIT_TIME_T
 			BASIC_LDFLAGS += -Wl,--large-address-aware