-fno-common

Index: src/main.h
--- src/main.h.orig
+++ src/main.h
@@ -35,10 +35,5 @@ extern int use_readline_flag;
 /* is default_shell unixy? */
 extern int unixy_shell;
 
-/**! The default value of SHELL and the shell that is used when issuing
-   commands on targets.
-*/
-extern char *default_shell;
-
 /*! Print version information. */
 extern void print_version (void);