objtool: Reorganize cmdline options

Split the existing options into two groups: actions, which actually do
something; and options, which modify the actions in some way.

Also there's no need to have short flags for all the non-action options.
Reserve short flags for the more important actions.

While at it:

- change a few of the short flags to be more intuitive

- make option descriptions more consistently descriptive

- sort options in the source like they are when printed

- move options to a global struct

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Link: https://lkml.kernel.org/r/9dcaa752f83aca24b1b21f0b0eeb28a0c181c0b0.1650300597.git.jpoimboe@redhat.com

tools/objtool/include/objtool/builtin.h

@@ -8,9 +8,29 @@
 #include <subcmd/parse-options.h>
 
 extern const struct option check_options[];
-extern bool no_fp, no_unreachable, retpoline, module, backtrace, uaccess, stats,
-	    lto, vmlinux, mcount, noinstr, backup, sls, dryrun,
-	    ibt;
+
+struct opts {
+	/* actions: */
+	bool ibt;
+	bool mcount;
+	bool noinstr;
+	bool retpoline;
+	bool sls;
+	bool uaccess;
+
+	/* options: */
+	bool backtrace;
+	bool backup;
+	bool dryrun;
+	bool lto;
+	bool module;
+	bool no_fp;
+	bool no_unreachable;
+	bool stats;
+	bool vmlinux;
+};
+
+extern struct opts opts;
 
 extern int cmd_parse_options(int argc, const char **argv, const char * const usage[]);