parser: Add warning flag for ABI messages

ABI warnings can be to much for a deployed system. Add

  --warn=abi

to control output of abi warnings

MR: https://gitlab.com/apparmor/apparmor/-/merge_requests/600
Signed-off-by: John Johansen <john.johansen@canonical.com>

parser/parser.h

@@ -54,6 +54,7 @@ extern int parser_token;
 
 #define WARN_RULE_NOT_ENFORCED	1
 #define WARN_RULE_DOWNGRADED	2
+#define WARN_ABI		4
 
 extern dfaflags_t warnflags;
 
@@ -331,6 +332,8 @@ extern int read_implies_exec;
 extern void pwarn(const char *fmt, ...) __attribute__((__format__(__printf__, 1, 2)));
 extern void common_warn_once(const char *name, const char *msg, const char **warned_name);
 
+#define pwarn_onflag(F, args...) do { if (warnflags & (F)) pwarn(args); } while (0)
+
 /* from parser_main (cannot be used in tst builds) */
 extern int force_complain;
 extern void display_version(void);