Extract usage information into a separate file.

logname.c

@@ -23,12 +23,6 @@
 #include "internal.h"
 #include <stdio.h>
 
-static const char logname_usage[] = "logname\n"
-#ifndef BB_FEATURE_TRIVIAL_HELP
-	"\nPrint the name of the current user.\n"
-#endif
-	;
-
 extern int logname_main(int argc, char **argv)
 {
 	char *user = xmalloc(9);