kbuild: declare the modpost error functions as printf like

This way gcc can warn for wrong format strings
Signed-off-by: Andi Kleen <[e-mail]>
Signed-off-by: Sam Ravnborg <[e-mail]>

scripts/mod/modpost.c

···
 	export_unused_gpl, export_gpl_future, export_unknown
 };
 
-void fatal(const char *fmt, ...)
+#define PRINTF __attribute__ ((format (printf, 1, 2)))
+
+PRINTF void fatal(const char *fmt, ...)
 {
 	va_list arglist;
 
···
 	exit(1);
 }
 
-void warn(const char *fmt, ...)
+PRINTF void warn(const char *fmt, ...)
 {
 	va_list arglist;
 
···
 	va_end(arglist);
 }
 
-void merror(const char *fmt, ...)
+PRINTF void merror(const char *fmt, ...)
 {
 	va_list arglist;