Import strsep() from musl libc

Makefile

@@ -53,7 +53,8 @@ LIBUTILSRC =\
 	libutil/sha512.c\
 	libutil/strcasestr.c\
 	libutil/strlcat.c\
-	libutil/strlcpy.c
+	libutil/strlcpy.c\
+	libutil/strsep.c
 
 LIB = $(LIBUTF) $(LIBUTIL)
 

libutil/strsep.c

@@ -0,0 +1,37 @@
+/*
+ * Copyright 2005-2014 Rich Felker, et al.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+*/
+#include <string.h>
+
+#include "../util.h"
+
+char *
+strsep(char **str, const char *sep)
+{
+	char *s = *str, *end;
+	if (!s) return NULL;
+	end = s + strcspn(s, sep);
+	if (*end) *end++ = 0;
+	else end = 0;
+	*str = end;
+	return s;
+}

util.h

@@ -41,6 +41,9 @@ size_t strlcat(char *, const char *, size_t);
 #undef strlcpy
 size_t strlcpy(char *, const char *, size_t);
 
+#undef strsep
+char *strsep(char **, const char *);
+
 /* regex */
 int enregcomp(int, regex_t *, const char *, int);
 int eregcomp(regex_t *, const char *, int);