-fno-common

Index: src/globals.h
--- src/globals.h.orig
+++ src/globals.h
@@ -89,6 +89,12 @@ extern int in_debugger;
 extern bool b_debugger_preread;
 
 /* Remember the original value of the SHELL variable, from the environment.  */
-struct variable shell_var;
+extern struct variable shell_var;
+
+/**! The default value of SHELL and the shell that is used when issuing
+   commands on targets.
+*/
+extern const char *default_shell;
+
 
 #endif /*GLOBALS_H*/
