Can you try with ./configure --disable-asm

With ./configure --disable-asm the build succeeeds.

Based on this I discovered that macOS aarch64 assembly uses "%%" as separator instead ";". On macOS ";" is marker for start of comment. This also means that none of the Aarch64 assembly (SHA&AES acceleration, etc) has not been building for macOS aarch64 builds.

If it (clang with the name of gcc) can support other assembler with -no-integrated-as, it's worth a try.

No, for Apple Silicon, /usr/bin/as is Apple's LLVM assembler. So, -no-integrated-as won't work.

I looked LLVM, and the separator seems hard-coded as (in llvm-project/compiler-rt/lib/builtins/assembly.h):

#if defined(__APPLE__) && defined(__aarch64__)
#define SEPARATOR %%
#else
#define SEPARATOR ;
#endif

So, there seems no way but we need to modify our source code.

Side note:

• For 32-bit ARM, GNU as has an option --mccs (TI CodeComposer Studio syntax compatibility mode) to allow the comment line with ;,
• Internally, GNU as has support to change the separator character(s) (possibly at runtime like 32-bit ARM), but it does not support string like %%.

BTW, homebrew uses --disable-asm option of configure.

For ;, here is a possible patch (it doesn't support the case of GNU as on macOS aarch64, though):

There may be other syntax differences (and errors). Please try.

I found that cfarm.net has macOS machine where I can test building. There's few issues to solve:

1. Global symbols need prefix underscore. Need to handle this for:
   • configure.ac aarch64 asm checks
   • cipher/ aarch64 assembly files
2. read-only data section, SECTION_RODATA, needs to be defined differently (.section __TEXT,__const)
3. %% separator instead of ; in assembly files
4. Local asm labels start with L instead of .L

I'm thinking of using additional preprocessor script to handle 3. and 4. bulk conversions on darwin-aarch64. So in configure.ac we'd setup CCAS="\$(SHELL) \$(top_srcdir)/build-aux/darwin-aarch64-as.sh $CCAS" if host is aarch64-apple-darwin.

Here's patch (tested with macOS aarch64 machine cfarm104.cfarm.net):

Since my apple-silicon.diff doesn't work with GNU Toolchain, I think that the approach is not better.

@jukivili 's patch is better, IIUC, it even works well when a user uses GNU Toolchain, since it won't introduce %% but replacing ';' into newline by the additional script.

Pushed to master.