LibC: Rewrite all the headers.

We now have more or less posix issue 2018 conforming libc headers.

This was a really time consuming and boring operation but it had to
be done.

Now we get to actually start implementing libc :)

libc/include/net/if.h

@@ -0,0 +1,25 @@
+#ifndef _NET_IF_H
+#define _NET_IF_H 1
+
+// https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/net_if.h.html
+
+#include <sys/cdefs.h>
+
+#define IF_NAMESIZE 16
+
+__BEGIN_DECLS
+
+struct if_nameindex
+{
+	unsigned if_index;	/* Numeric index of the interface. */
+	char* if_name;		/* Null-terminated name of the interface. */
+};
+
+void					if_freenameindex(struct if_nameindex* ptr);
+char*					if_indextoname(unsigned ifindex, char* ifname);
+struct if_nameindex*	if_nameindex(void);
+unsigned				if_nametoindex(const char* ifname);
+
+__END_DECLS
+
+#endif