+
+## Specifics
+
+### getopt\_long
+
+`getopt_long.h` has additional macros related to argument
+permuting, defining those enables it (GNU behaviour):
+
+```
+#define GETOPT_PERMUTE_ARGS
+#define GETOPT_LONG_PERMUTE_ARGS
+#define GETOPT_LONG_ONLY_PERMUTE_ARGS
+```