[Bug go/84484] New: libgo configure tests fail to find -latomic

["schwab at linux-m68k dot org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84484

            Bug ID: 84484
           Summary: libgo configure tests fail to find -latomic
           Product: gcc
           Version: 8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: go
          Assignee: ian at airs dot com
          Reporter: schwab@linux-m68k.org
                CC: cmang at google dot com
  Target Milestone: ---
            Target: riscv*-*-*

When building for riscv the compiler wants to link -latomic when building with
-pthread, but the configure tests in libgo that use $PTHREAD_CFLAGS fail due to
not finding -latomic.

configure:14889: checking for sem_timedwait
configure:14889:
/home/abuild/rpmbuild/BUILD/gcc-8.0.1+r257516/obj-riscv64-suse-linux/./gcc/xgcc
-B/home/abuild/rpmbuild/BUILD/gcc-8.0.1+r257516/obj-riscv64-suse-linux/./gcc/
-B/usr/riscv64-suse-linux/bin/ -B/usr/riscv64-suse-linux/lib/ -isystem
/usr/riscv64-suse-linux/include -isystem /usr/riscv64-suse-linux/sys-include   
-o conftest -fmessage-length=0 -grecord-gcc-switches -O2 -D_FORTIFY_SOURCE=2
-funwind-tables -fasynchronous-unwind-tables -fstack-clash-protection -g
-U_FORTIFY_SOURCE -pthread   conftest.c  -lpthread >&5
/usr/riscv64-suse-linux/bin/ld: cannot find -latomic
collect2: error: ld returned 1 exit status
configure:14889: $? = 1