diff --git a/libc/bionic/__memcpy_chk.cpp b/libc/bionic/__memcpy_chk.cpp
deleted file mode 100644
index 9463954..0000000
--- a/libc/bionic/__memcpy_chk.cpp
+++ /dev/null
@@ -1,38 +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 <string.h>
-
-#include "private/bionic_fortify.h"
-
-// Runtime implementation of __memcpy_chk (used directly by compiler, not in headers).
-extern "C" void* __memcpy_chk(void* dst, const void* src, size_t count, size_t dst_len) {
-  __check_count("memcpy", "count", count);
-  __check_buffer_access("memcpy", "write into", count, dst_len);
-  return memcpy(dst, src, count);
-}
diff --git a/libc/bionic/__strcat_chk.cpp b/libc/bionic/__strcat_chk.cpp
deleted file mode 100644
index 16b2327..0000000
--- a/libc/bionic/__strcat_chk.cpp
+++ /dev/null
@@ -1,50 +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 <string.h>
-
-#include "private/bionic_fortify.h"
-
-// Runtime implementation of __builtin____strcat_chk (used directly by compiler, not in headers).
-extern "C" char* __strcat_chk(char* __restrict dst, const char* __restrict src,
-                              size_t dst_buf_size) {
-  char* save = dst;
-  size_t dst_len = __strlen_chk(dst, dst_buf_size);
-
-  dst += dst_len;
-  dst_buf_size -= dst_len;
-
-  while ((*dst++ = *src++) != '\0') {
-    dst_buf_size--;
-    if (__predict_false(dst_buf_size == 0)) {
-      __fortify_fatal("strcat: prevented write past end of %zu-byte buffer", dst_buf_size);
-    }
-  }
-
-  return save;
-}
diff --git a/libc/bionic/__strcpy_chk.cpp b/libc/bionic/__strcpy_chk.cpp
deleted file mode 100644
index 6fbfb8b..0000000
--- a/libc/bionic/__strcpy_chk.cpp
+++ /dev/null
@@ -1,39 +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 <string.h>
-
-#include "private/bionic_fortify.h"
-
-// Runtime implementation of __builtin____strcpy_chk (used directly by compiler, not in headers).
-extern "C" char* __strcpy_chk(char* dst, const char* src, size_t dst_len) {
-  // TODO: optimize so we don't scan src twice.
-  size_t src_len = strlen(src) + 1;
-  __check_buffer_access("strcpy", "write into", src_len, dst_len);
-  return strcpy(dst, src);
-}
diff --git a/libc/bionic/fortify.cpp b/libc/bionic/fortify.cpp
index b888f09..4a7ff13 100644
--- a/libc/bionic/fortify.cpp
+++ b/libc/bionic/fortify.cpp
@@ -456,3 +456,43 @@
   __check_buffer_access("write", "read from", count, buf_size);
   return write(fd, buf, count);
 }
+
+#if !defined(NO___STRCAT_CHK)
+// Runtime implementation of __builtin____strcat_chk (used directly by compiler, not in headers).
+extern "C" char* __strcat_chk(char* __restrict dst, const char* __restrict src,
+                              size_t dst_buf_size) {
+  char* save = dst;
+  size_t dst_len = __strlen_chk(dst, dst_buf_size);
+
+  dst += dst_len;
+  dst_buf_size -= dst_len;
+
+  while ((*dst++ = *src++) != '\0') {
+    dst_buf_size--;
+    if (__predict_false(dst_buf_size == 0)) {
+      __fortify_fatal("strcat: prevented write past end of %zu-byte buffer", dst_buf_size);
+    }
+  }
+
+  return save;
+}
+#endif // NO___STRCAT_CHK
+
+#if !defined(NO___STRCPY_CHK)
+// Runtime implementation of __builtin____strcpy_chk (used directly by compiler, not in headers).
+extern "C" char* __strcpy_chk(char* dst, const char* src, size_t dst_len) {
+  // TODO: optimize so we don't scan src twice.
+  size_t src_len = strlen(src) + 1;
+  __check_buffer_access("strcpy", "write into", src_len, dst_len);
+  return strcpy(dst, src);
+}
+#endif // NO___STRCPY_CHK
+
+#if !defined(NO___MEMCPY_CHK)
+// Runtime implementation of __memcpy_chk (used directly by compiler, not in headers).
+extern "C" void* __memcpy_chk(void* dst, const void* src, size_t count, size_t dst_len) {
+  __check_count("memcpy", "count", count);
+  __check_buffer_access("memcpy", "write into", count, dst_len);
+  return memcpy(dst, src, count);
+}
+#endif // NO___MEMCPY_CHK