Index: newlib/libc/include/sys/signal.h
===================================================================
RCS file: /cvs/src/src/newlib/libc/include/sys/signal.h,v
retrieving revision 1.21
diff -u -r1.21 signal.h
--- newlib/libc/include/sys/signal.h	8 Aug 2012 11:04:16 -0000	1.21
+++ newlib/libc/include/sys/signal.h	22 Jan 2013 20:46:29 -0000
@@ -101,6 +101,15 @@
 #define sa_sigaction  _signal_handlers._sigaction
 #endif
 
+/*
+ * Structure used in sigaltstack call.
+ */
+typedef struct sigalstack {
+  void     *ss_sp;    /* Stack base or pointer.  */
+  size_t    ss_size;  /* Stack size.  */
+  int       ss_flags; /* Flags.  */
+} stack_t;
+
 #elif defined(__CYGWIN__)
 #include <cygwin/signal.h>
 #else
@@ -158,6 +167,10 @@
 int _EXFUN(sigsuspend, (const sigset_t *));
 int _EXFUN(sigpause, (int));
 
+#if defined(__rtems__)
+int _EXFUN(sigaltstack, (const stack_t *, stack_t *));
+#endif
+
 #if defined(_POSIX_THREADS)
 #ifdef __CYGWIN__
 #  ifndef _CYGWIN_TYPES_H