Replace direct inclusions of c.h with inclusion of postgres.h,

to ensure that config.h is included as well.

src/interfaces/libpq/pqsignal.h

@@ -6,7 +6,7 @@
  *
  * Copyright (c) 1994, Regents of the University of California
  *
- * $Id: pqsignal.h,v 1.5 1998/09/01 04:40:15 momjian Exp $
+ * $Id: pqsignal.h,v 1.6 1999/01/17 03:04:57 tgl Exp $
  *
  * NOTES
  *	  This shouldn't be in libpq, but the monitor and some other
@@ -17,7 +17,7 @@
 #ifndef PQSIGNAL_H
 #define PQSIGNAL_H
 
-#include "c.h"
+#include "postgres.h"
 
 typedef void (*pqsigfunc) (int);