diff --git a/libc/bionic/__fgets_chk.cpp b/libc/bionic/__fgets_chk.cpp
index 61dad7077..c09f6c531 100644
--- a/libc/bionic/__fgets_chk.cpp
+++ b/libc/bionic/__fgets_chk.cpp
@@ -26,6 +26,8 @@
  * SUCH DAMAGE.
  */
 
+#undef _FORTIFY_SOURCE
+
 #include <stdio.h>
 #include <stdlib.h>
 #include "private/libc_logging.h"
diff --git a/libc/bionic/__memmove_chk.cpp b/libc/bionic/__memmove_chk.cpp
index 26bd646cd..b88a94f76 100644
--- a/libc/bionic/__memmove_chk.cpp
+++ b/libc/bionic/__memmove_chk.cpp
@@ -26,6 +26,8 @@
  * SUCH DAMAGE.
  */
 
+#undef _FORTIFY_SOURCE
+
 #include <string.h>
 #include <stdlib.h>
 #include "private/libc_logging.h"
diff --git a/libc/bionic/__memset_chk.cpp b/libc/bionic/__memset_chk.cpp
index 9a3be19dd..5f20452f5 100644
--- a/libc/bionic/__memset_chk.cpp
+++ b/libc/bionic/__memset_chk.cpp
@@ -26,6 +26,8 @@
  * SUCH DAMAGE.
  */
 
+#undef _FORTIFY_SOURCE
+
 #include <string.h>
 #include <stdlib.h>
 #include "private/libc_logging.h"
diff --git a/libc/bionic/__strlcat_chk.cpp b/libc/bionic/__strlcat_chk.cpp
index f583154ae..2b7373b9d 100644
--- a/libc/bionic/__strlcat_chk.cpp
+++ b/libc/bionic/__strlcat_chk.cpp
@@ -26,6 +26,8 @@
  * SUCH DAMAGE.
  */
 
+#undef _FORTIFY_SOURCE
+
 #include <string.h>
 #include <stdlib.h>
 #include "private/libc_logging.h"
diff --git a/libc/bionic/__strlcpy_chk.cpp b/libc/bionic/__strlcpy_chk.cpp
index ebf1444b9..6b2187932 100644
--- a/libc/bionic/__strlcpy_chk.cpp
+++ b/libc/bionic/__strlcpy_chk.cpp
@@ -26,6 +26,8 @@
  * SUCH DAMAGE.
  */
 
+#undef _FORTIFY_SOURCE
+
 #include <string.h>
 #include <stdlib.h>
 #include "private/libc_logging.h"
diff --git a/libc/bionic/__strncpy_chk.cpp b/libc/bionic/__strncpy_chk.cpp
index 76458aa74..9625929cd 100644
--- a/libc/bionic/__strncpy_chk.cpp
+++ b/libc/bionic/__strncpy_chk.cpp
@@ -26,6 +26,8 @@
  * SUCH DAMAGE.
  */
 
+#undef _FORTIFY_SOURCE
+
 #include <string.h>
 #include <stdlib.h>
 #include "private/libc_logging.h"
diff --git a/libc/bionic/__vsnprintf_chk.cpp b/libc/bionic/__vsnprintf_chk.cpp
index 8550224b3..8c0911162 100644
--- a/libc/bionic/__vsnprintf_chk.cpp
+++ b/libc/bionic/__vsnprintf_chk.cpp
@@ -26,6 +26,8 @@
  * SUCH DAMAGE.
  */
 
+#undef _FORTIFY_SOURCE
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdarg.h>
diff --git a/libc/bionic/__vsprintf_chk.cpp b/libc/bionic/__vsprintf_chk.cpp
index bd2aeaba5..5914026b0 100644
--- a/libc/bionic/__vsprintf_chk.cpp
+++ b/libc/bionic/__vsprintf_chk.cpp
@@ -26,6 +26,8 @@
  * SUCH DAMAGE.
  */
 
+#undef _FORTIFY_SOURCE
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdarg.h>