Update Musl Libc code

We now have implement all of Musl's localization code, the same way that
Musl implements localization. You may need setlocale(LC_ALL, "C.UTF-8"),
just in case anything stops working as expected.

third_party/musl/ctime.c

@@ -0,0 +1,22 @@
+/*-*- mode:c;indent-tabs-mode:t;c-basic-offset:8;tab-width:8;coding:utf-8   -*-│
+│ vi: set noet ft=c ts=8 sw=8 fenc=utf-8                                   :vi │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/weirdtypes.h"
+#include "libc/time.h"
+
+/**
+ * Represents time as string.
+ * @threadunsafe
+ */
+char *
+ctime(const time_t *timep)
+{
+	/*
+	** Section 4.12.3.2 of X3.159-1989 requires that
+	**	The ctime function converts the calendar time pointed to by timer
+	**	to local time in the form of a string. It is equivalent to
+	**		asctime(localtime(timer))
+	*/
+	struct tm *tmp = localtime(timep);
+	return tmp ? asctime(tmp) : NULL;
+}