build: Fix Linux/x86 bootstrap without --with-gnu-as/--with-as [PR123841]

build: Fix Linux/x86 bootstrap  without --with-gnu-as/--with-as [PR123841]

My recent patch r16-7073 broke Linux/x86 bootstrap without
--with-gnu-as/with-as by only setting gcc_cv_as_flags in acinclude.m4
with gas_flag=yes.  Instead it should allow for any value.

Bootstrapped without regressions on x86_64-pc-linux-gnu,
i386-pc-solaris2.11 --with-gnu-as --with-as, and and
x86_64-apple-darwin21.6.0 (both in state 2 now with gcc/auto-host.h
unchanged).

2026-01-27  Jakub Jelinek  <jakub@redhat.com>

	gcc:
	PR other/123841
	* acinclude.m4 (gcc_GAS_FLAGS) <i?86-*-* | x86_64-*-*>: Set
	gcc_cv_as_flags irrespective of $gas_flag.
	* configure: Regenerate.