[Bug target/95128] aarch64: configure option for outline-atomics

[albert at tugraz dot at]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95128

--- Comment #3 from Christopher Albert <albert at tugraz dot at> ---
Created attachment 63970
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=63970&action=edit
Patch: disable outline-atomics by default on aarch64-netbsd

Proposed patch: add -mno-outline-atomics to CC1_SPEC in aarch64-netbsd.h
unless the user explicitly passes -moutline-atomics.

NetBSD libgcc does not include t-lse, so the out-of-line atomic helpers
(__aarch64_ldadd4_relax etc.) are never built.  The LSE runtime detection
in lse-init.c is also Linux-specific.

Tested on cfarm428 (NetBSD 10.1, aarch64) together with the PR124512 fix:
check-gfortran drops from 421 failures to 48 (all remaining are NetBSD
runtime issues in 7 tests, unrelated to atomics or CAF).

See also PR95129 for the runtime detection side.