Lets not just paper over this. Add implementation of __xpg_sigpause()

include/signal.h

@@ -159,7 +159,7 @@ extern int sigpause (int __mask) __THROW __attribute_deprecated__;
 # define sigpause(mask) __sigpause ((mask), 0)
 #else
 # ifdef __USE_XOPEN
-#  if 0 /* def __GNUC__ */
+#  ifdef __GNUC__
 extern int sigpause (int __sig) __asm__ ("__xpg_sigpause");
 #  else
 /* Remove a signal from the signal mask and suspend the process.  */

libc/signal/sigpause.c

@@ -63,3 +63,9 @@ int sigpause (int mask)
 {
   return __sigpause (mask, 0);
 }
+
+int __xpg_sigpause (int sig)
+{
+  return __sigpause (sig, 1);
+}
+