diff --git a/libc/Android.mk b/libc/Android.mk
index fd81d7e..88225d6 100644
--- a/libc/Android.mk
+++ b/libc/Android.mk
@@ -209,7 +209,6 @@
 	string/strstr.c \
 	string/strtok.c \
 	string/strtotimeval.c \
-	string/strxfrm.c \
 	string/__memcpy_chk.c \
 	string/__memmove_chk.c \
 	string/__memset_chk.c \
@@ -338,6 +337,9 @@
 	regex/regexec.c \
 	regex/regfree.c \
 
+libc_upstream_netbsd_src_files := \
+	upstream-netbsd/libc/string/strxfrm.c \
+
 # The following files are common, but must be compiled
 # with different C flags when building a static C library.
 #
@@ -677,18 +679,39 @@
 
 
 # ========================================================
+# libc_netbsd.a - upstream NetBSD C library code
+# ========================================================
+#
+# These files are built with the netbsd-compat.h header file
+# automatically included.
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := $(libc_upstream_netbsd_src_files)
+LOCAL_CFLAGS := \
+    $(libc_common_cflags) \
+    -include upstream-netbsd/netbsd-compat.h
+LOCAL_C_INCLUDES := $(libc_common_c_includes)
+LOCAL_MODULE := libc_netbsd
+LOCAL_SYSTEM_SHARED_LIBRARIES :=
+
+include $(BUILD_STATIC_LIBRARY)
+
+
+# ========================================================
 # libc_common.a
 # ========================================================
+
 include $(CLEAR_VARS)
 
 LOCAL_SRC_FILES := $(libc_common_src_files)
 LOCAL_CFLAGS := $(libc_common_cflags)
 ifeq ($(TARGET_ARCH),arm)
-LOCAL_CFLAGS += -DCRT_LEGACY_WORKAROUND
+    LOCAL_CFLAGS += -DCRT_LEGACY_WORKAROUND
 endif
 LOCAL_C_INCLUDES := $(libc_common_c_includes)
 LOCAL_MODULE := libc_common
-LOCAL_WHOLE_STATIC_LIBRARIES := libbionic_ssp
+LOCAL_WHOLE_STATIC_LIBRARIES := libbionic_ssp libc_netbsd
 LOCAL_SYSTEM_SHARED_LIBRARIES :=
 
 include $(BUILD_STATIC_LIBRARY)
diff --git a/libc/NOTICE b/libc/NOTICE
index 8c5bdc8..d78b840 100644
--- a/libc/NOTICE
+++ b/libc/NOTICE
@@ -1850,6 +1850,22 @@
 
 -------------------------------------------------------------------
 
+Copyright (C) 2012 The Android Open Source Project
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+     http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+
+-------------------------------------------------------------------
+
 Copyright (c) 1991 by AT&T.
 
 Permission to use, copy, modify, and distribute this software for any
diff --git a/libc/string/strxfrm.c b/libc/string/strxfrm.c
deleted file mode 100755
index 3c4d707..0000000
--- a/libc/string/strxfrm.c
+++ /dev/null
@@ -1,47 +0,0 @@
-/*
- * Copyright (C) 2009 The Android Open Source Project
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *  * Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- *  * Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in
- *    the documentation and/or other materials provided with the
- *    distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
- * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
- * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
- * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
- * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
- * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
- * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
- * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- */
-#include <string.h>
-
-/*
- * Transform string s2 to string s1 using the current locale so that
- * strcmp of transformed strings yields the same result as strcoll.
- * Since Bionic really does not support locales, we assume we always use
- * the C locale.
- *
- * This function is provided to make libstdc++-v3 usable.
- */
-size_t
-strxfrm(char *s1, const char *s2, size_t n)
-{
-	size_t len = strlen(s2) + 1;
-
-	if (len < n)
-		n = len;
-	memcpy(s1, s2, n);
-	return len;
-}
diff --git a/libc/upstream-netbsd/README.txt b/libc/upstream-netbsd/README.txt
new file mode 100644
index 0000000..86af6eb
--- /dev/null
+++ b/libc/upstream-netbsd/README.txt
@@ -0,0 +1,9 @@
+This directory contains upstream NetBSD source. You should not edit these
+files directly. Make fixes upstream and then pull down the new version of
+the file.
+
+Note that code in the other 'netbsd' directory contains Android modifications.
+We should work towards getting as many of those changes as possible upstream
+and then losing those files in favor of pure upstream copies here instead.
+
+TODO: write a script to make this process automated.
diff --git a/libc/upstream-netbsd/libc/string/strxfrm.c b/libc/upstream-netbsd/libc/string/strxfrm.c
new file mode 100644
index 0000000..42c2a24
--- /dev/null
+++ b/libc/upstream-netbsd/libc/string/strxfrm.c
@@ -0,0 +1,70 @@
+/*	$NetBSD: strxfrm.c,v 1.12 2012/06/25 22:32:46 abs Exp $	*/
+
+/*-
+ * Copyright (c) 1990, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Chris Torek.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+#if defined(LIBC_SCCS) && !defined(lint)
+#if 0
+static char sccsid[] = "@(#)strxfrm.c	8.1 (Berkeley) 6/4/93";
+#else
+__RCSID("$NetBSD: strxfrm.c,v 1.12 2012/06/25 22:32:46 abs Exp $");
+#endif
+#endif /* LIBC_SCCS and not lint */
+
+#include <assert.h>
+#include <string.h>
+
+/*
+ * Transform src, storing the result in dst, such that
+ * strcmp() on transformed strings returns what strcoll()
+ * on the original untransformed strings would return.
+ */
+size_t
+strxfrm(char *dst, const char *src, size_t n)
+{
+	size_t srclen, copysize;
+
+	_DIAGASSERT(src != NULL);
+
+	/*
+	 * Since locales are unimplemented, this is just a copy.
+	 */
+	srclen = strlen(src);
+	if (n != 0) {
+		_DIAGASSERT(dst != NULL);
+		copysize = srclen < n ? srclen : n - 1;
+		(void)memcpy(dst, src, copysize);
+		dst[copysize] = 0;
+	}
+	return (srclen);
+}
diff --git a/libc/upstream-netbsd/netbsd-compat.h b/libc/upstream-netbsd/netbsd-compat.h
new file mode 100644
index 0000000..a52052a
--- /dev/null
+++ b/libc/upstream-netbsd/netbsd-compat.h
@@ -0,0 +1,24 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef _BIONIC_NETBSD_COMPAT_H_included
+#define _BIONIC_NETBSD_COMPAT_H_included
+
+// NetBSD uses _DIAGASSERT to null-check arguments and the like.
+#include <assert.h>
+#define _DIAGASSERT(e) ((e) ? (void) 0 : __assert2(__FILE__, __LINE__, __func__, #e))
+
+#endif