ddb(4): Move an extern variable declaration to a header

Trivial cleanup, no functional change.

sys/ddb/db_command.h

@@ -49,6 +49,7 @@ void	db_command_init(void);
 void	db_command_loop(void);
 void	db_command_script(const char *command);
 
+extern int		db_cmd_loop_done;
 extern db_addr_t	db_dot;		/* current location */
 extern db_addr_t	db_last_addr;	/* last explicit address typed */
 extern db_addr_t	db_prev;	/* last address examined

sys/ddb/db_run.c

@@ -48,8 +48,9 @@ __FBSDID("$FreeBSD$");
 #include <vm/vm.h>
 
 #include <ddb/ddb.h>
-#include <ddb/db_break.h>
 #include <ddb/db_access.h>
+#include <ddb/db_break.h>
+#include <ddb/db_command.h>
 
 #define	STEP_ONCE	1
 #define	STEP_RETURN	2
@@ -332,8 +333,6 @@ db_clear_single_step(void)
 
 #endif	/* SOFTWARE_SSTEP */
 
-extern int	db_cmd_loop_done;
-
 /* single-step */
 /*ARGSUSED*/
 void