diff --git a/libc/bionic/__fgets_chk.cpp b/libc/bionic/__fgets_chk.cpp
index 61dad70..c09f6c5 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 26bd646..b88a94f 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 9a3be19..5f20452 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 f583154..2b7373b 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 ebf1444..6b21879 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 76458aa..9625929 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 8550224..8c09111 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 bd2aeab..5914026 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>