-fno-common

Index: src/globals.h
--- src/globals.h.orig
+++ src/globals.h
@@ -100,4 +100,9 @@ extern bool b_debugger_preread;
 /* Remember the original value of the SHELL variable, from the environment.  */
 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*/