(sigunblock): Don't define if already defined.

diff --git a/src/syssignal.h b/src/syssignal.h
index eafdb3a6a6a442816cddaacd1dab33601e4e85cb..2ea83b68b902d414e280f43975e0d1b9f6e88e1e 100644 (file)
--- a/src/syssignal.h
+++ b/src/syssignal.h
@@ -86,19 +86,25 @@ extern SIGMASKTYPE sigprocmask_set;
       sigprocmask (SIG_BLOCK, &sigprocmask_set, NULL))
 #endif
 
+#ifndef sigunblock
 #define sigunblock(sig)                                                \
      (sigprocmask_set = SIGFULLMASK & ~(sig),                  \
       sigprocmask (SIG_SETMASK, &sigprocmask_set, NULL))
+#endif
 
 #else
 #ifdef USG
 
+#ifndef sigunblock
 #define sigunblock(sig) 
+#endif
 
 #else
 
+#ifndef sigunblock
 #define sigunblock(SIG) \
 { SIGMASKTYPE omask = sigblock (SIGEMPTYMASK); sigsetmask (omask & ~SIG); }
+#endif
 
 #endif /* ! defined (USG) */
 #endif /* ! defined (USG5_4) */