#include "target.h" less wildly

Don't include "target.h" from more headers than necessary.  This
avoids needless interdependencies and duplicated include paths.

Don't needlessly include it in source files, either.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>

src/target/target_request.h

@@ -26,7 +26,8 @@
 #ifndef TARGET_REQUEST_H
 #define TARGET_REQUEST_H
 
-#include "target.h"
+struct target;
+struct command_context;
 
 typedef enum target_req_cmd
 {