Add support for CLANGARM64 target

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

Author: dennisameling

.github/workflows/clang-build.yml

@@ -0,0 +1,35 @@
+name: CLANG build
+
+on:
+  pull_request:
+
+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
+        shell: bash
+        run: |
+          cat <<EOF >> /etc/pacman.conf
+          [clangarm64]
+          Server = https://mirror.msys2.org/mingw/clangarm64/
+          EOF
+          pacman -Sy
+      - name: Install packages
+        shell: bash
+        # The clangarm64 folder is missing in the Git for Windows SDK, so let's create it
+        run: |
+          mkdir -p /clangarm64
+          pacman -S --noconfirm 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
+      - shell: bash
+        run: make -j8

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

@@ -656,7 +656,9 @@ ifeq ($(uname_S),MINGW)
 	USE_WIN32_IPC = YesPlease
 	USE_WIN32_MMAP = YesPlease
 	MMAP_PREVENTS_DELETE = UnfortunatelyYes
-	USE_NED_ALLOCATOR = YesPlease
+	ifneq (CLANGARM64,$(MSYSTEM))
+		USE_NED_ALLOCATOR = YesPlease
+	endif
 	UNRELIABLE_FSTAT = UnfortunatelyYes
 	OBJECT_CREATION_USES_RENAMES = UnfortunatelyNeedsTo
 	NO_REGEX = YesPlease
@@ -711,6 +713,10 @@ else
 			prefix = /mingw64
 			HOST_CPU = x86_64
 			BASIC_LDFLAGS += -Wl,--pic-executable,-e,mainCRTStartup
+		else ifeq (CLANGARM64,$(MSYSTEM))
+			prefix = /clangarm64
+			HOST_CPU = aarch64
+			BASIC_LDFLAGS += -Wl,--pic-executable,-e,mainCRTStartup
 		else
 			COMPAT_CFLAGS += -D_USE_32BIT_TIME_T
 			BASIC_LDFLAGS += -Wl,--large-address-aware
@@ -726,7 +732,9 @@ else
 		USE_GETTEXT_SCHEME = fallthrough
 		USE_LIBPCRE = YesPlease
 		NO_CURL =
-		USE_NED_ALLOCATOR = YesPlease
+		ifneq (CLANGARM64,$(MSYSTEM))
+			USE_NED_ALLOCATOR = YesPlease
+		endif
 		NO_PYTHON =
 		ifeq (/mingw64,$(subst 32,64,$(prefix)))
 			# Move system config into top-level /etc/