Index: uspace/lib/posix/Makefile
===================================================================
--- uspace/lib/posix/Makefile	(revision b501de784dd26902c687e3142fa124f7aecd3384)
+++ uspace/lib/posix/Makefile	(revision bfb11794075cbc477be69efdc4d991d5da43960c)
@@ -31,5 +31,5 @@
 LIBRARY = libposix
 
-EXTRA_CFLAGS = -Iinclude/posix
+EXTRA_CFLAGS = -Iinclude/posix -D_XOPEN_SOURCE
 
 EXPORT_FILES = \
Index: uspace/lib/posix/include/posix/string.h
===================================================================
--- uspace/lib/posix/include/posix/string.h	(revision b501de784dd26902c687e3142fa124f7aecd3384)
+++ uspace/lib/posix/include/posix/string.h	(revision bfb11794075cbc477be69efdc4d991d5da43960c)
@@ -59,6 +59,4 @@
 extern char *stpncpy(char *__restrict__ dest, const char *__restrict__ src, size_t n);
 extern void *memccpy(void *__restrict__ dest, const void *__restrict__ src, int c, size_t n);
-extern char *strdup(const char *s);
-extern char *strndup(const char *s, size_t n);
 
 /* Search Functions */
@@ -70,7 +68,4 @@
 /* Error Messages */
 extern int strerror_r(int errnum, char *buf, size_t bufsz);
-
-/* String Length */
-extern size_t strnlen(const char *s, size_t n);
 
 /* Signal Messages */
Index: uspace/lib/posix/src/string.c
===================================================================
--- uspace/lib/posix/src/string.c	(revision b501de784dd26902c687e3142fa124f7aecd3384)
+++ uspace/lib/posix/src/string.c	(revision bfb11794075cbc477be69efdc4d991d5da43960c)
@@ -135,38 +135,4 @@
 
 /**
- * Duplicate a string.
- *
- * @param s String to be duplicated.
- * @return Newly allocated copy of the string.
- */
-char *strdup(const char *s)
-{
-	return strndup(s, SIZE_MAX);
-}
-
-/**
- * Duplicate a specific number of bytes from a string.
- *
- * @param s String to be duplicated.
- * @param n Maximum length of the resulting string..
- * @return Newly allocated string copy of length at most n.
- */
-char *strndup(const char *s, size_t n)
-{
-	assert(s != NULL);
-
-	size_t len = strnlen(s, n);
-	char *dup = malloc(len + 1);
-	if (dup == NULL) {
-		return NULL;
-	}
-
-	memcpy(dup, s, len);
-	dup[len] = '\0';
-
-	return dup;
-}
-
-/**
  * Scan string for a first occurence of a character.
  *
@@ -225,25 +191,4 @@
 
 	return EOK;
-}
-
-/**
- * Get limited length of the string.
- *
- * @param s String which length shall be determined.
- * @param n Maximum number of bytes that can be examined to determine length.
- * @return The lower of either string length or n limit.
- */
-size_t strnlen(const char *s, size_t n)
-{
-	assert(s != NULL);
-
-	for (size_t sz = 0; sz < n; ++sz) {
-
-		if (s[sz] == '\0') {
-			return sz;
-		}
-	}
-
-	return n;
 }