sigmask is a macro which is dropped if BSD compatibility is
not enabled. So we check if the macro does not exist then
we define it to __sigmask

Upstream-Status: Inappropriate [configuration]
Signed-off-by: Khem Raj <raj.khem@gmail.com>

Index: strace-4.5.20/signal.c
===================================================================
--- strace-4.5.20.orig/signal.c	2010-02-23 13:26:16.000000000 -0800
+++ strace-4.5.20/signal.c	2011-07-20 23:06:35.842339197 -0700
@@ -140,6 +140,11 @@
 #endif
 #endif /* LINUX */
 
+#if !defined (sigmask) && defined (__sigmask)
+/* Compute mask for signal SIG.  */
+#define sigmask(sig)   __sigmask(sig)
+#endif /* sigmask */
+
 const char *const signalent0[] = {
 #include "signalent.h"
 };