Rever the strmem() addition and add a TODO element

strmem() was not very well thought out. The thing is the following:
If the string contains a zero character, we want to match it, and not
stop right there in place.

The "real" solution is to use memmem() where needed and replace all
functions that assume zero-terminated-strings from standard input, which
could lead to early string-breakoffs.
This requires a strict tracking of string lengths.

Makefile

@@ -75,7 +75,6 @@ LIBUTILSRC =\
 	libutil/strcasestr.c\
 	libutil/strlcat.c\
 	libutil/strlcpy.c\
-	libutil/strmem.c\
 	libutil/strsep.c\
 	libutil/strtonum.c\
 	libutil/unescape.c

TODO

@@ -15,5 +15,8 @@ If you are looking for some work to do on sbase, another option is to
 pick a utility from the list in the README which has missing flags or
 features noted.
 
+What also needs to be implemented is the capability of the tools to
+handle data with NUL-bytes in it.
+
 [0] http://landley.net/toybox/roadmap.html
 [1] http://git.suckless.org/ubase/

join.c

@@ -225,7 +225,7 @@ makeline(char *s, size_t len)
 		beg = sp;
 
 		if (sep) {
-			if (!(end = strmem(sp, sep, seplen)))
+			if (!(end = utfutf(sp, sep)))
 				eol = 1;
 
 			if (!eol) {

libutil/strmem.c

@@ -1,23 +0,0 @@
-/* See LICENSE file for copyright and license details. */
-#include <stddef.h>
-#include <string.h>
-
-char *
-strmem(char *haystack, char *needle, size_t needlelen)
-{
-	size_t i;
-
-	for (i = 0; i < needlelen; i++) {
-		if (haystack[i] == '\0') {
-			return NULL;
-		}
-	}
-
-	for (; haystack[i]; i++) {
-		if (!(memcmp(haystack + i - needlelen, needle, needlelen))) {
-			return (haystack + i - needlelen);
-		}
-	}
-
-	return NULL;
-}

util.h

@@ -58,8 +58,6 @@ size_t estrlcpy(char *, const char *, size_t);
 #undef strsep
 char *strsep(char **, const char *);
 
-char *strmem(char *, char *, size_t);
-
 /* regex */
 int enregcomp(int, regex_t *, const char *, int);
 int eregcomp(regex_t *, const char *, int);