Fixes for -fno-common
https://github.com/rubund/graywolf/commit/f47937b66d4d44eafc4224f7c43d556dbf88f05b

Index: src/twsc/standard.h
--- src/twsc/standard.h.orig
+++ src/twsc/standard.h
@@ -304,7 +304,7 @@ EXTERN DOUBLE vertical_wire_weightG ;
 /* the configuration */
 EXTERN INT numcellsG ;
 EXTERN INT numtermsG ;
-EXTERN INT numnetsG ;
+extern INT numnetsG ;
 EXTERN INT numpadgrpsG ;
 EXTERN INT lastpadG ;
 EXTERN INT maxtermG ;
