sparc/sigaction: revert change. These semantics are needed for nptl

Signed-off-by: Austin Foxley <austinf@cetoncorp.com>

libc/sysdeps/linux/sparc/sigaction.c

@@ -34,8 +34,7 @@ _syscall5(int, rt_sigaction, int, a, int, b, int, c, int, d, int, e);
 static void __rt_sigreturn_stub(void);
 static void __sigreturn_stub(void);
 
-libc_hidden_proto(sigaction)
-int sigaction(int sig, const struct sigaction *act, struct sigaction *oact)
+int __libc_sigaction(int sig, const struct sigaction *act, struct sigaction *oact)
 {
 	int ret;
 	struct sigaction kact, koact;
@@ -66,8 +65,10 @@ int sigaction(int sig, const struct sigaction *act, struct sigaction *oact)
 	return ret;
 }
 
-libc_hidden_def(sigaction)
-weak_alias(sigaction,__libc_sigaction)
+#ifndef LIBC_SIGACTION
+weak_alias(__libc_sigaction,sigaction)
+libc_hidden_weak(sigaction)
+#endif
 
 static void
 __rt_sigreturn_stub(void)