sandbox: add getopt support

This adds simple command-line parsing to sandbox. The idea is that it
sets up the state with options provided, and this state can then be
queried later, as needed.

New flags are declared with the SB_CMDLINE_OPT_SHORT helper macro,
pointers are automatically gathered up in a special section, and
then the core code takes care of gathering them up and processing
at runtime.  This way there is no central place where we have to
store a list of flags with ifdefs.

Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

arch/sandbox/include/asm/state.h

@@ -22,6 +22,8 @@
 #ifndef __SANDBOX_STATE_H
 #define __SANDBOX_STATE_H
 
+#include <config.h>
+
 /* How we exited U-Boot */
 enum exit_type_id {
 	STATE_EXIT_NORMAL,
@@ -33,6 +35,9 @@ enum exit_type_id {
 struct sandbox_state {
 	const char *cmd;		/* Command to execute */
 	enum exit_type_id exit_type;	/* How we exited U-Boot */
+	const char *parse_err;		/* Error to report from parsing */
+	int argc;			/* Program arguments */
+	char **argv;
 };
 
 /**