Disable spurious -Wstringop-overflow for setjmp/longjmp (bug 26647)

[Joseph Myers]

Also, similar errors appear in the testsuite from __sigsetjmp calls in the 
installed pthread.h, and presumably would apply in user programs that use 
these pthread.h macros.  Should we apply a change like this one (with 
appropriate version conditionals and comments; as an installed header, it 
can't use libc-diag.h) to address such errors both for the glibc testsuite 
and for user programs?  (With this and the other three patches I've posted 
today, both glibc and its testsuite build OK for arm-linux-gnueabi.)

diff --git a/sysdeps/nptl/pthread.h b/sysdeps/nptl/pthread.h
index d4194da..ec77949 100644
--- a/sysdeps/nptl/pthread.h
+++ b/sysdeps/nptl/pthread.h
@@ -658,8 +658,11 @@ __pthread_cleanup_routine (struct __pthread_cleanup_frame *__frame)
     __pthread_unwind_buf_t __cancel_buf;				      \
     void (*__cancel_routine) (void *) = (routine);			      \
     void *__cancel_arg = (arg);						      \
+    _Pragma ("GCC diagnostic push");					      \
+    _Pragma ("GCC diagnostic ignored \"-Wstringop-overflow=\"");	      \
     int __not_first_call = __sigsetjmp ((struct __jmp_buf_tag *) (void *)     \
 					__cancel_buf.__cancel_jmp_buf, 0);    \
+    _Pragma ("GCC diagnostic pop");					      \
     if (__glibc_unlikely (__not_first_call))				      \
       {									      \
 	__cancel_routine (__cancel_arg);				      \
@@ -693,8 +696,11 @@ extern void __pthread_unregister_cancel (__pthread_unwind_buf_t *__buf)
     __pthread_unwind_buf_t __cancel_buf;				      \
     void (*__cancel_routine) (void *) = (routine);			      \
     void *__cancel_arg = (arg);						      \
+    _Pragma ("GCC diagnostic push");					      \
+    _Pragma ("GCC diagnostic ignored \"-Wstringop-overflow=\"");	      \
     int __not_first_call = __sigsetjmp ((struct __jmp_buf_tag *) (void *)     \
 					__cancel_buf.__cancel_jmp_buf, 0);    \
+    _Pragma ("GCC diagnostic pop");					      \
     if (__glibc_unlikely (__not_first_call))				      \
       {									      \
 	__cancel_routine (__cancel_arg);				      \

-- 
Joseph S. Myers
joseph@codesourcery.com