diff --git a/Makefile.am b/Makefile.am
index b08b0ba..fc7e426 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -61,14 +61,6 @@ if !HAVE_STRLCPY
 libcompat_la_SOURCES += compat/strlcpy.c
 endif
 
-if !HAVE_STRNDUP
-libcompat_la_SOURCES += compat/strndup.c
-# the only user of strnlen is strndup, so only build it if needed
-if !HAVE_STRNLEN
-libcompat_la_SOURCES += compat/strnlen.c
-endif
-endif
-
 if !HAVE_STRTONUM
 libcompat_la_SOURCES += compat/strtonum.c
 endif
diff --git a/configure.ac b/configure.ac
index 6c2c548..26557cc 100644
--- a/configure.ac
+++ b/configure.ac
@@ -80,7 +80,7 @@ AC_CHECK_FUNCS([arc4random_uniform asprintf explicit_bzero])
 AC_CHECK_FUNCS([getentropy memmem poll reallocarray])
 AC_CHECK_FUNCS([setproctitle setgroups])
 AC_CHECK_FUNCS([setregid setresgid setreuid setresuid])
-AC_CHECK_FUNCS([strlcat strlcpy strndup strnlen strtonum])
+AC_CHECK_FUNCS([strlcat strlcpy strtonum])
 
 # check auxiliary libraries that might contain other functions
 AC_SEARCH_LIBS([arc4random], [crypto])
@@ -114,8 +114,6 @@ AM_CONDITIONAL([HAVE_SETPROCTITLE], [test "x$ac_cv_func_setproctitle" = xyes])
 AM_CONDITIONAL([HAVE_SHA512], [test "x$ac_cv_func_SHA512Init" = xyes])
 AM_CONDITIONAL([HAVE_STRLCAT], [test "x$ac_cv_func_strlcat" = xyes])
 AM_CONDITIONAL([HAVE_STRLCPY], [test "x$ac_cv_func_strlcpy" = xyes])
-AM_CONDITIONAL([HAVE_STRNDUP], [test "x$ac_cv_func_strndup" = xyes])
-AM_CONDITIONAL([HAVE_STRNLEN], [test "x$ac_cv_func_strnlen" = xyes])
 AM_CONDITIONAL([HAVE_STRTONUM], [test "x$ac_cv_func_strtonum" = xyes])
 
 # overrides for arc4random_buf implementations with known issues
diff --git a/include/string.h b/include/string.h
index c458154..1981107 100644
--- a/include/string.h
+++ b/include/string.h
@@ -17,24 +17,21 @@
 #include <strings.h>
 #endif
 
-#ifndef HAVE_STRLCPY
-size_t strlcpy(char *dst, const char *src, size_t siz);
+#ifndef HAVE_EXPLICIT_BZERO
+void explicit_bzero(void *, size_t);
 #endif
 
-#ifndef HAVE_STRLCAT
-size_t strlcat(char *dst, const char *src, size_t siz);
+#ifndef HAVE_MEMMEM
+void * memmem(const void *big, size_t big_len, const void *little,
+	size_t little_len);
 #endif
 
-#ifndef HAVE_STRNDUP
-char * strndup(const char *str, size_t maxlen);
-/* the only user of strnlen is strndup, so only build it if needed */
-#ifndef HAVE_STRNLEN
-size_t strnlen(const char *str, size_t maxlen);
-#endif
+#ifndef HAVE_STRLCAT
+size_t strlcat(char *dst, const char *src, size_t siz);
 #endif
 
-#ifndef HAVE_EXPLICIT_BZERO
-void explicit_bzero(void *, size_t);
+#ifndef HAVE_STRLCPY
+size_t strlcpy(char *dst, const char *src, size_t siz);
 #endif
 
 #ifndef HAVE_TIMINGSAFE_BCMP
@@ -45,11 +42,6 @@ int timingsafe_bcmp(const void *b1, const void *b2, size_t n);
 int timingsafe_memcmp(const void *b1, const void *b2, size_t len);
 #endif
 
-#ifndef HAVE_MEMMEM
-void * memmem(const void *big, size_t big_len, const void *little,
-	size_t little_len);
-#endif
-
 #ifdef _WIN32
 #include <errno.h>
 
diff --git a/update.sh b/update.sh
index 71875f8..142bc25 100755
--- a/update.sh
+++ b/update.sh
@@ -35,7 +35,7 @@ cp $libutil_src/imsg.c compat/
 cp $libutil_src/imsg-buffer.c compat/
 (cd compat; $PATCH < $patches/patch-imsg.c)
 
-for i in explicit_bzero.c strlcpy.c strlcat.c strndup.c strnlen.c; do
+for i in explicit_bzero.c strlcpy.c strlcat.c; do
 	$CP $libc_src/string/$i compat
 done
 $CP $libc_src/stdlib/reallocarray.c compat