Remove locale-cancer from grep(1)

What in the actual fuck? Check the ml history on why we won't use
locale() functions in this context.

grep.c

@@ -1,5 +1,4 @@
 /* See LICENSE file for copyright and license details. */
-#include <locale.h>
 #include <regex.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -179,8 +178,6 @@ main(int argc, char *argv[])
 	FILE *fp;
 	char *arg;
 
-	setlocale(LC_ALL, "");
-
 	SLIST_INIT(&phead);
 
 	ARGBEGIN {