diff --git a/libc/bionic/__fgets_chk.c b/libc/bionic/__fgets_chk.cpp
similarity index 96%
rename from libc/bionic/__fgets_chk.c
rename to libc/bionic/__fgets_chk.cpp
index 19123b9..780cf16 100644
--- a/libc/bionic/__fgets_chk.c
+++ b/libc/bionic/__fgets_chk.cpp
@@ -41,7 +41,7 @@
  * This fgets check is called if _FORTIFY_SOURCE is defined and
  * greater than 0.
  */
-char *__fgets_chk(char *dest, int supplied_size,
+extern "C" char *__fgets_chk(char *dest, int supplied_size,
                   FILE *stream, size_t dest_len_from_compiler)
 {
     if (supplied_size < 0) {
diff --git a/libc/bionic/__memcpy_chk.c b/libc/bionic/__memcpy_chk.cpp
similarity index 96%
rename from libc/bionic/__memcpy_chk.c
rename to libc/bionic/__memcpy_chk.cpp
index 10334ba..991ff02 100644
--- a/libc/bionic/__memcpy_chk.c
+++ b/libc/bionic/__memcpy_chk.cpp
@@ -42,7 +42,7 @@
  * This memcpy check is called if _FORTIFY_SOURCE is defined and
  * greater than 0.
  */
-void *__memcpy_chk(void *dest, const void *src,
+extern "C" void *__memcpy_chk(void *dest, const void *src,
               size_t copy_amount, size_t dest_len)
 {
     if (__builtin_expect(copy_amount > dest_len, 0)) {
diff --git a/libc/bionic/__memmove_chk.c b/libc/bionic/__memmove_chk.cpp
similarity index 96%
rename from libc/bionic/__memmove_chk.c
rename to libc/bionic/__memmove_chk.cpp
index 529eb8f..1867d71 100644
--- a/libc/bionic/__memmove_chk.c
+++ b/libc/bionic/__memmove_chk.cpp
@@ -41,7 +41,7 @@
  * This memmove check is called if _FORTIFY_SOURCE is defined and
  * greater than 0.
  */
-void *__memmove_chk (void *dest, const void *src,
+extern "C" void *__memmove_chk (void *dest, const void *src,
               size_t len, size_t dest_len)
 {
     if (len > dest_len) {
diff --git a/libc/bionic/__memset_chk.c b/libc/bionic/__memset_chk.cpp
similarity index 95%
rename from libc/bionic/__memset_chk.c
rename to libc/bionic/__memset_chk.cpp
index 0904c03..97c5c38 100644
--- a/libc/bionic/__memset_chk.c
+++ b/libc/bionic/__memset_chk.cpp
@@ -41,8 +41,7 @@
  * This memset check is called if _FORTIFY_SOURCE is defined and
  * greater than 0.
  */
-void *__memset_chk (void *dest, int c, size_t n, size_t dest_len)
-{
+extern "C" void *__memset_chk (void *dest, int c, size_t n, size_t dest_len) {
     if (n > dest_len) {
         __libc_android_log_print(ANDROID_LOG_FATAL, "libc",
             "*** memset buffer overflow detected ***\n");
diff --git a/libc/bionic/__snprintf_chk.c b/libc/bionic/__snprintf_chk.c
deleted file mode 100644
index dbda3db..0000000
--- a/libc/bionic/__snprintf_chk.c
+++ /dev/null
@@ -1,59 +0,0 @@
-/*
- * Copyright (C) 2012 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 <stdio.h>
-#include <stdarg.h>
-
-/*
- * Runtime implementation of __builtin____snprintf_chk.
- *
- * See
- *   http://gcc.gnu.org/onlinedocs/gcc/Object-Size-Checking.html
- *   http://gcc.gnu.org/ml/gcc-patches/2004-09/msg02055.html
- * for details.
- *
- * This snprintf check is called if _FORTIFY_SOURCE is defined and
- * greater than 0.
- */
-int __snprintf_chk(
-        char *dest,
-        size_t supplied_size,
-        int flags,
-        size_t dest_len_from_compiler,
-        const char *format, ...)
-{
-    va_list va;
-    int retval;
-
-    va_start(va, format);
-    retval = __vsnprintf_chk(dest, supplied_size, flags,
-                             dest_len_from_compiler, format, va);
-    va_end(va);
-
-    return retval;
-}
diff --git a/libc/bionic/__sprintf_chk.c b/libc/bionic/__sprintf_chk.c
deleted file mode 100644
index 67acbe1..0000000
--- a/libc/bionic/__sprintf_chk.c
+++ /dev/null
@@ -1,58 +0,0 @@
-/*
- * Copyright (C) 2012 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 <stdio.h>
-#include <stdarg.h>
-
-/*
- * Runtime implementation of __builtin____sprintf_chk.
- *
- * See
- *   http://gcc.gnu.org/onlinedocs/gcc/Object-Size-Checking.html
- *   http://gcc.gnu.org/ml/gcc-patches/2004-09/msg02055.html
- * for details.
- *
- * This sprintf check is called if _FORTIFY_SOURCE is defined and
- * greater than 0.
- */
-int __sprintf_chk(
-        char *dest,
-        int flags,
-        size_t dest_len_from_compiler,
-        const char *format, ...)
-{
-    va_list va;
-    int retval;
-
-    va_start(va, format);
-    retval = __vsprintf_chk(dest, flags,
-                             dest_len_from_compiler, format, va);
-    va_end(va);
-
-    return retval;
-}
diff --git a/libc/bionic/__strcat_chk.c b/libc/bionic/__strcat_chk.cpp
similarity index 96%
rename from libc/bionic/__strcat_chk.c
rename to libc/bionic/__strcat_chk.cpp
index 4665d66..ec194fc 100644
--- a/libc/bionic/__strcat_chk.c
+++ b/libc/bionic/__strcat_chk.cpp
@@ -42,8 +42,7 @@
  * This strcat check is called if _FORTIFY_SOURCE is defined and
  * greater than 0.
  */
-char *__strcat_chk (char *dest, const char *src, size_t dest_buf_size)
-{
+extern "C" char *__strcat_chk (char *dest, const char *src, size_t dest_buf_size) {
     // TODO: optimize so we don't scan src/dest twice.
     size_t src_len  = strlen(src);
     size_t dest_len = strlen(dest);
diff --git a/libc/bionic/__strcpy_chk.c b/libc/bionic/__strcpy_chk.cpp
similarity index 95%
rename from libc/bionic/__strcpy_chk.c
rename to libc/bionic/__strcpy_chk.cpp
index 79486b4..1d45ea2 100644
--- a/libc/bionic/__strcpy_chk.c
+++ b/libc/bionic/__strcpy_chk.cpp
@@ -41,8 +41,7 @@
  * This strcpy check is called if _FORTIFY_SOURCE is defined and
  * greater than 0.
  */
-char *__strcpy_chk (char *dest, const char *src, size_t dest_len)
-{
+extern "C" char *__strcpy_chk (char *dest, const char *src, size_t dest_len) {
     // TODO: optimize so we don't scan src twice.
     size_t src_len = strlen(src) + 1;
     if (src_len > dest_len) {
diff --git a/libc/bionic/__strlcat_chk.c b/libc/bionic/__strlcat_chk.cpp
similarity index 96%
rename from libc/bionic/__strlcat_chk.c
rename to libc/bionic/__strlcat_chk.cpp
index b895fb8..05b7d7d 100644
--- a/libc/bionic/__strlcat_chk.c
+++ b/libc/bionic/__strlcat_chk.cpp
@@ -42,7 +42,7 @@
  * This strlcat check is called if _FORTIFY_SOURCE is defined and
  * greater than 0.
  */
-size_t __strlcat_chk(char *dest, const char *src,
+extern "C" size_t __strlcat_chk(char *dest, const char *src,
               size_t supplied_size, size_t dest_len_from_compiler)
 {
     if (supplied_size > dest_len_from_compiler) {
diff --git a/libc/bionic/__strlcpy_chk.c b/libc/bionic/__strlcpy_chk.cpp
similarity index 96%
rename from libc/bionic/__strlcpy_chk.c
rename to libc/bionic/__strlcpy_chk.cpp
index 752c86c..bf98037 100644
--- a/libc/bionic/__strlcpy_chk.c
+++ b/libc/bionic/__strlcpy_chk.cpp
@@ -42,7 +42,7 @@
  * This strlcpy check is called if _FORTIFY_SOURCE is defined and
  * greater than 0.
  */
-size_t __strlcpy_chk(char *dest, const char *src,
+extern "C" size_t __strlcpy_chk(char *dest, const char *src,
               size_t supplied_size, size_t dest_len_from_compiler)
 {
     if (supplied_size > dest_len_from_compiler) {
diff --git a/libc/bionic/__strlen_chk.c b/libc/bionic/__strlen_chk.cpp
similarity index 96%
rename from libc/bionic/__strlen_chk.c
rename to libc/bionic/__strlen_chk.cpp
index 43e7e80..67410d4 100644
--- a/libc/bionic/__strlen_chk.c
+++ b/libc/bionic/__strlen_chk.cpp
@@ -53,8 +53,7 @@
  *
  * or anytime strlen reads beyond an object boundary.
  */
-size_t __strlen_chk(const char *s, size_t s_len)
-{
+extern "C" size_t __strlen_chk(const char *s, size_t s_len) {
     size_t ret = strlen(s);
 
     if (__builtin_expect(ret >= s_len, 0)) {
diff --git a/libc/bionic/__strncat_chk.c b/libc/bionic/__strncat_chk.cpp
similarity index 97%
rename from libc/bionic/__strncat_chk.c
rename to libc/bionic/__strncat_chk.cpp
index 2036c9f..2ba8550 100644
--- a/libc/bionic/__strncat_chk.c
+++ b/libc/bionic/__strncat_chk.cpp
@@ -42,7 +42,7 @@
  * This strncat check is called if _FORTIFY_SOURCE is defined and
  * greater than 0.
  */
-char *__strncat_chk (char *dest, const char *src,
+extern "C" char *__strncat_chk (char *dest, const char *src,
               size_t len, size_t dest_buf_size)
 {
     // TODO: optimize so we don't scan src/dest twice.
diff --git a/libc/bionic/__strncpy_chk.c b/libc/bionic/__strncpy_chk.cpp
similarity index 96%
rename from libc/bionic/__strncpy_chk.c
rename to libc/bionic/__strncpy_chk.cpp
index 3f9e9fb..875d092 100644
--- a/libc/bionic/__strncpy_chk.c
+++ b/libc/bionic/__strncpy_chk.cpp
@@ -41,7 +41,7 @@
  * This strncpy check is called if _FORTIFY_SOURCE is defined and
  * greater than 0.
  */
-char *__strncpy_chk (char *dest, const char *src,
+extern "C" char *__strncpy_chk (char *dest, const char *src,
               size_t len, size_t dest_len)
 {
     if (len > dest_len) {
diff --git a/libc/bionic/__umask_chk.c b/libc/bionic/__umask_chk.cpp
similarity index 97%
rename from libc/bionic/__umask_chk.c
rename to libc/bionic/__umask_chk.cpp
index 5bb6a3b..df066b2 100644
--- a/libc/bionic/__umask_chk.c
+++ b/libc/bionic/__umask_chk.cpp
@@ -41,8 +41,7 @@
  * This umask check is called if _FORTIFY_SOURCE is defined and
  * greater than 0.
  */
-mode_t __umask_chk(mode_t mode)
-{
+extern "C" mode_t __umask_chk(mode_t mode) {
     if ((mode & 0777) != mode) {
         __libc_android_log_print(ANDROID_LOG_FATAL, "libc",
             "*** FORTIFY_SOURCE: umask called with invalid mask ***\n");
diff --git a/libc/bionic/__vsnprintf_chk.c b/libc/bionic/__vsnprintf_chk.cpp
similarity index 74%
rename from libc/bionic/__vsnprintf_chk.c
rename to libc/bionic/__vsnprintf_chk.cpp
index a1a1039..b4f534b 100644
--- a/libc/bionic/__vsnprintf_chk.c
+++ b/libc/bionic/__vsnprintf_chk.cpp
@@ -42,10 +42,10 @@
  * This vsnprintf check is called if _FORTIFY_SOURCE is defined and
  * greater than 0.
  */
-int __vsnprintf_chk(
+extern "C" int __vsnprintf_chk(
         char *dest,
         size_t supplied_size,
-        int flags,
+        int /*flags*/,
         size_t dest_len_from_compiler,
         const char *format,
         va_list va)
@@ -58,3 +58,32 @@
 
     return vsnprintf(dest, supplied_size, format, va);
 }
+
+/*
+ * Runtime implementation of __builtin____snprintf_chk.
+ *
+ * See
+ *   http://gcc.gnu.org/onlinedocs/gcc/Object-Size-Checking.html
+ *   http://gcc.gnu.org/ml/gcc-patches/2004-09/msg02055.html
+ * for details.
+ *
+ * This snprintf check is called if _FORTIFY_SOURCE is defined and
+ * greater than 0.
+ */
+extern "C" int __snprintf_chk(
+        char *dest,
+        size_t supplied_size,
+        int flags,
+        size_t dest_len_from_compiler,
+        const char *format, ...)
+{
+    va_list va;
+    int retval;
+
+    va_start(va, format);
+    retval = __vsnprintf_chk(dest, supplied_size, flags,
+                             dest_len_from_compiler, format, va);
+    va_end(va);
+
+    return retval;
+}
diff --git a/libc/bionic/__vsprintf_chk.c b/libc/bionic/__vsprintf_chk.cpp
similarity index 75%
rename from libc/bionic/__vsprintf_chk.c
rename to libc/bionic/__vsprintf_chk.cpp
index 8a809fc..00010cf 100644
--- a/libc/bionic/__vsprintf_chk.c
+++ b/libc/bionic/__vsprintf_chk.cpp
@@ -42,9 +42,9 @@
  * This vsprintf check is called if _FORTIFY_SOURCE is defined and
  * greater than 0.
  */
-int __vsprintf_chk(
+extern "C" int __vsprintf_chk(
         char *dest,
-        int flags,
+        int /*flags*/,
         size_t dest_len_from_compiler,
         const char *format,
         va_list va)
@@ -59,3 +59,31 @@
 
     return ret;
 }
+
+/*
+ * Runtime implementation of __builtin____sprintf_chk.
+ *
+ * See
+ *   http://gcc.gnu.org/onlinedocs/gcc/Object-Size-Checking.html
+ *   http://gcc.gnu.org/ml/gcc-patches/2004-09/msg02055.html
+ * for details.
+ *
+ * This sprintf check is called if _FORTIFY_SOURCE is defined and
+ * greater than 0.
+ */
+extern "C" int __sprintf_chk(
+        char *dest,
+        int flags,
+        size_t dest_len_from_compiler,
+        const char *format, ...)
+{
+    va_list va;
+    int retval;
+
+    va_start(va, format);
+    retval = __vsprintf_chk(dest, flags,
+                             dest_len_from_compiler, format, va);
+    va_end(va);
+
+    return retval;
+}