runtime/cgo: ignore -Watomic-alignment in gcc_libinit.c
When cross-compiling a cgo program with CC=clang for Linux/ARMv5,
atomic warnings cause build errors, as cgo uses -Werror.
These warnings seem to be harmless and come from the usage of
__atomic_load_n, which is emulated due to the lack of atomic
instructions in armv5.
Fixes #65290
Change-Id: Ie72efb77468f06888f81f15850401dc8ce2c78f9
GitHub-Last-Rev:
fbad847b962f6b4599cd843018e79f4b55be097e
GitHub-Pull-Request: golang/go#65588
Reviewed-on: https://go-review.googlesource.com/c/go/+/562348
Auto-Submit: Ian Lance Taylor <iant@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>