fix for -fno-common

--- generic/util.h.orig	Tue Jan 29 10:09:38 2008
+++ generic/util.h	Tue Feb  2 07:43:51 2021
@@ -48,7 +48,6 @@
 #   define TMP "/tmp"
 #endif
 
-Tcl_DString Result;
 extern Tcl_DString Result;
 
 int printres(const char *fmt, ...);