Fix warning in setjmp/jmpbug.c

[Joseph Myers]

This patch fixes a "set but not used" warning in setjmp/jmpbug.c.  A
variable is used only to store the result of alloca.  A cast to void
is added to avoid the warning, and the variable is made volatile to
ensure the call to alloca isn't optimized away for being unused.

Tested for x86_64.

2014-11-26  Joseph Myers  <joseph@codesourcery.com>

	* setjmp/jmpbug.c (test): Make foo volatile and cast it to
	void.

diff --git a/setjmp/jmpbug.c b/setjmp/jmpbug.c
index 125977b..8594c5a 100644
--- a/setjmp/jmpbug.c
+++ b/setjmp/jmpbug.c
@@ -14,7 +14,7 @@ static void
 test (int x)
 {
   jmp_buf buf;
-  char *foo;
+  char *volatile foo;
   int arr[100];
 
   arr[77] = x;
@@ -25,6 +25,7 @@ test (int x)
     }
 
   foo = (char *) alloca (128);
+  (void) foo;
   sub5 (buf);
 }
 

-- 
Joseph S. Myers
joseph@codesourcery.com