gh-130478: fix HACL* build for macOS Silicon (#134188)

configure.ac

@@ -8001,6 +8001,15 @@ AC_SUBST([LIBHACL_CFLAGS])
 LIBHACL_LDFLAGS=  # for now, no specific linker flags are needed
 AC_SUBST([LIBHACL_LDFLAGS])
 
+dnl Check if universal2 HACL* implementation should be used.
+if test "$UNIVERSAL_ARCHS" = "universal2" -o \
+   \( "$build_cpu" = "aarch64" -a "$build_vendor" = "apple" \)
+then
+  use_hacl_universal2_impl=yes
+else
+  use_hacl_universal2_impl=no
+fi
+
 # The SIMD files use aligned_alloc, which is not available on older versions of
 # Android.
 # The *mmintrin.h headers are x86-family-specific, so can't be used on WASI.
@@ -8017,7 +8026,7 @@ then
     # available on x86_64. However, performance of the HACL SIMD128 implementation
     # isn't great, so it's disabled on ARM64.
     AC_MSG_CHECKING([for HACL* SIMD128 implementation])
-    if test "$UNIVERSAL_ARCHS" == "universal2"; then
+    if test "$use_hacl_universal2_impl" = "yes"; then
       [LIBHACL_BLAKE2_SIMD128_OBJS="Modules/_hacl/Hacl_Hash_Blake2s_Simd128_universal2.o"]
       AC_MSG_RESULT([universal2])
     else
@@ -8049,7 +8058,7 @@ then
     # implementation requires symbols that aren't available on ARM64. Use a
     # wrapped implementation if we're building for universal2.
     AC_MSG_CHECKING([for HACL* SIMD256 implementation])
-    if test "$UNIVERSAL_ARCHS" == "universal2"; then
+    if test "$use_hacl_universal2_impl" = "yes"; then
       [LIBHACL_BLAKE2_SIMD256_OBJS="Modules/_hacl/Hacl_Hash_Blake2b_Simd256_universal2.o"]
       AC_MSG_RESULT([universal2])
     else