Fixed symbol search for defining NSIG. It now also checks _NSIG
which some C libs define (e.g. glibc).
Added a fallback default value for NSIG which hopefully provides
enough room for signal slots.
diff --git a/Modules/signalmodule.c b/Modules/signalmodule.c
index f75ec43..1c11fdd 100644
--- a/Modules/signalmodule.c
+++ b/Modules/signalmodule.c
@@ -35,11 +35,15 @@
#endif
#ifndef NSIG
-#ifdef _SIGMAX
-#define NSIG (_SIGMAX + 1) /* For QNX */
-#else
-#define NSIG (SIGMAX + 1) /* for djgpp */
-#endif
+# if defined(_NSIG)
+# define NSIG _NSIG /* For BSD/SysV */
+# elif defined(_SIGMAX)
+# define NSIG (_SIGMAX + 1) /* For QNX */
+# elif defined(SIGMAX)
+# define NSIG (SIGMAX + 1) /* For djgpp */
+# else
+# define NSIG 64 /* Use a reasonable default value */
+# endif
#endif