libdecnumber: Change gstdint.h to stdint.h

Replace the inclusion of gstdint.h with the standard stdint.h
header file.
Signed-off-by: NTom Musta <tommusta@gmail.com>
Signed-off-by: NAlexander Graf <agraf@suse.de>

include/libdecnumber/decContext.h

@@ -56,7 +56,7 @@
   #define DECCFULLNAME "Decimal Context Descriptor"   /* Verbose name */
   #define DECCAUTHOR   "Mike Cowlishaw"		      /* Who to blame */
 
-  #include "gstdint.h"		   /* C99 standard integers	      */
+  #include <stdint.h>
   #include <stdio.h>		   /* for printf, etc.		      */
   #include <signal.h>		   /* for traps			      */