Versions of the assembler using clang from XCode 12.5/12.5.1
have a bug which produces different code layout between debug and
non-debug input, leading to a compare fail for default configure
parameters.
This is a workaround fix to disable the optimisation that is
responsible for the bug.
* config.in: Regenerate.
* config/i386/darwin.h (EXTRA_ASM_OPTS): New
(ASM_SPEC): Pass options to disable branch shortening where
needed.
* configure: Regenerate.
* configure.ac: Detect versions of 'as' that support the
optimisation which has the bug.