libcflat: add format checking to report()

report() is a wrapper for printf(), but the compiler was not aware.
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>

lib/libcflat.h

@@ -96,14 +96,20 @@ extern int vsnprintf(char *buf, int size, const char *fmt, va_list va)
 extern int vprintf(const char *fmt, va_list va)
 					__attribute__((format(printf, 1, 0)));
 
-void report_prefix_pushf(const char *prefix_fmt, ...);
+void report_prefix_pushf(const char *prefix_fmt, ...)
+					__attribute__((format(printf, 1, 2)));
 extern void report_prefix_push(const char *prefix);
 extern void report_prefix_pop(void);
-extern void report(const char *msg_fmt, bool pass, ...);
-extern void report_xfail(const char *msg_fmt, bool xfail, bool pass, ...);
-extern void report_abort(const char *msg_fmt, ...);
-extern void report_skip(const char *msg_fmt, ...);
-extern void report_info(const char *msg_fmt, ...);
+extern void report(const char *msg_fmt, bool pass, ...)
+					__attribute__((format(printf, 1, 3)));
+extern void report_xfail(const char *msg_fmt, bool xfail, bool pass, ...)
+					__attribute__((format(printf, 1, 4)));
+extern void report_abort(const char *msg_fmt, ...)
+					__attribute__((format(printf, 1, 2)));
+extern void report_skip(const char *msg_fmt, ...)
+					__attribute__((format(printf, 1, 2)));
+extern void report_info(const char *msg_fmt, ...)
+					__attribute__((format(printf, 1, 2)));
 extern void report_pass(void);
 extern int report_summary(void);