[gn build] Manually port llvm/lib/Support/BLAKE3

Author: MaskRay

llvm/utils/gn/secondary/llvm/lib/Support/BUILD.gn

@@ -45,6 +45,9 @@ static_library("Support") {
     "ARMWinEH.cpp",
     "Allocator.cpp",
     "AutoConvert.cpp",
+    "BLAKE3/blake3.c",
+    "BLAKE3/blake3_dispatch.c",
+    "BLAKE3/blake3_portable.c",
     "BinaryStreamError.cpp",
     "BinaryStreamReader.cpp",
     "BinaryStreamRef.cpp",
@@ -181,6 +184,8 @@ static_library("Support") {
     "Watchdog.cpp",
   ]
 
+  defines = ["BLAKE3_NO_AVX512", "BLAKE3_NO_AVX2", "BLAKE3_NO_SSE41", "BLAKE3_NO_SSE2", "BLAKE3_USE_NEON=0"]
+
   libs = []
 
   # FIXME: llvm/Config/BUILD.gn currently always sets LLVM_WITH_Z3