bug#57849: 29.0.50; MacOS ld warning from native compilation

[Gerd Möllmann]

And trying libgccjit HEAD fails...

/opt/homebrew/opt/ > brew install libgccjit --HEAD
==> Cloning https://gcc.gnu.org/git/gcc.git
Cloning into '/Users/gerd/Library/Caches/Homebrew/libgccjit--git'...
Updating files: 100% (117196/117196), done.
==> Checking out branch master
Already on 'master'
Your branch is up to date with 'origin/master'.
==> ../configure --prefix=/opt/homebrew/Cellar/libgccjit/HEAD-39dc665 
--libdir=/opt/homebrew/Cellar/libgccjit/HEAD-3
==> make
Last 15 lines from /Users/gerd/Library/Logs/Homebrew/libgccjit/02.make:
checking for struct tms... yes
checking for clock_t... yes
checking for F_SETLKW... yes
checking for O_CLOEXEC... yes
checking for fcntl.h... (cached) yes
checking whether O_NONBLOCK is declared... yes
checking for AF_UNIX... yes
checking for AF_INET6... yes
checking for _LK_LOCK... no
checking if mkdir takes one argument... no
/private/tmp/libgccjit-20220916-39022-19zntmh/gcc/configure: line 12693: 
test: =: unary operator expected
*** Configuration aarch64-apple-darwin21 not supported
make[2]: *** [configure-stage1-gcc] Error 1
make[1]: *** [stage1-bubble] Error 2
make: *** [all] Error 2