test/rmlvo-to-keymap: drop basename usage

It wants some libgen.h include which is POSIX only, let's just remove
it as it's hardly important.

Signed-off-by: Ran Benita <ran234@gmail.com>

test/rmlvo-to-keymap.c

@@ -37,7 +37,7 @@ static void
 usage(char **argv)
 {
     printf("Usage: %s [--print] [--rules <rules>] [--layout <layout>] [--variant <variant>] [--options <option>]\n",
-           basename(argv[0]));
+           argv[0]);
     printf("This tool tests the compilation from RMLVO to a keymap.\n");
     printf("--print  print the resulting keymap\n");
 }