Remove incorrect guards around inclusion of <signal.h>

Causes problems with UNIX03/SUSv3

p4raw-id: //depot/perl@21916

diff --git a/doio.c b/doio.c
index 40287f9..dc192d4 100644 (file)
--- a/doio.c
+++ b/doio.c
@@ -48,9 +48,7 @@
 #  define OPEN_EXCL 0
 #endif
 
-#if !defined(NSIG) || defined(M_UNIX) || defined(__unix) || defined(M_XENIX)
 #include <signal.h>
-#endif
 
 bool
 Perl_do_open(pTHX_ GV *gv, register char *name, I32 len, int as_raw,