diff --git a/libc/bionic/pthread_internal.h b/libc/bionic/pthread_internal.h
index 0eb0e0a93..316a14a28 100644
--- a/libc/bionic/pthread_internal.h
+++ b/libc/bionic/pthread_internal.h
@@ -30,6 +30,7 @@
 
 #include <pthread.h>
 #include <stdbool.h>
+#include <sys/cdefs.h>
 
 __BEGIN_DECLS
 
diff --git a/libc/include/mntent.h b/libc/include/mntent.h
index b83da1f2f..8b87f718d 100644
--- a/libc/include/mntent.h
+++ b/libc/include/mntent.h
@@ -29,6 +29,7 @@
 #define _MNTENT_H_
 
 #include <stdio.h>
+#include <sys/cdefs.h>
 
 #define MNTTYPE_IGNORE "ignore"
 
diff --git a/libc/include/netinet/in.h b/libc/include/netinet/in.h
index c5b964e08..bf3b498c4 100644
--- a/libc/include/netinet/in.h
+++ b/libc/include/netinet/in.h
@@ -29,11 +29,13 @@
 #define _NETINET_IN_H_
 
 #include <endian.h>
+#include <netinet/in6.h>
+#include <sys/cdefs.h>
 #include <sys/socket.h>
+
 #include <linux/in.h>
 #include <linux/in6.h>
 #include <linux/ipv6.h>
-#include <netinet/in6.h>
 
 __BEGIN_DECLS
 
diff --git a/libc/include/sys/auxv.h b/libc/include/sys/auxv.h
index 918442f54..0d753c3d8 100644
--- a/libc/include/sys/auxv.h
+++ b/libc/include/sys/auxv.h
@@ -29,6 +29,7 @@
 #define _SYS_AUXV_H_
 
 #include <linux/auxvec.h>
+#include <sys/cdefs.h>
 
 __BEGIN_DECLS
 
diff --git a/libc/include/sys/signalfd.h b/libc/include/sys/signalfd.h
index c03a0e9c7..a249d658f 100644
--- a/libc/include/sys/signalfd.h
+++ b/libc/include/sys/signalfd.h
@@ -29,8 +29,9 @@
 #ifndef _SYS_SIGNALFD_H_
 #define _SYS_SIGNALFD_H_
 
-#include <signal.h>
 #include <linux/signalfd.h>
+#include <signal.h>
+#include <sys/cdefs.h>
 
 __BEGIN_DECLS
 
diff --git a/libc/include/sys/timeb.h b/libc/include/sys/timeb.h
index f2cc39cc8..cf6f25581 100644
--- a/libc/include/sys/timeb.h
+++ b/libc/include/sys/timeb.h
@@ -28,6 +28,7 @@
 #ifndef _SYS_TIMEB_H
 #define _SYS_TIMEB_H
 
+#include <sys/cdefs.h>
 #include <sys/time.h>
 
 __BEGIN_DECLS
diff --git a/libc/netbsd/net/reentrant.h b/libc/netbsd/net/reentrant.h
index 15507ebe9..60bff089e 100644
--- a/libc/netbsd/net/reentrant.h
+++ b/libc/netbsd/net/reentrant.h
@@ -102,6 +102,7 @@
 
 #include <pthread.h>
 #include <signal.h>
+#include <sys/cdefs.h>
 
 #define	mutex_t			pthread_mutex_t
 #define	MUTEX_INITIALIZER	PTHREAD_MUTEX_INITIALIZER
diff --git a/libc/private/bionic_auxv.h b/libc/private/bionic_auxv.h
index 69d15b6f8..23b2e3794 100644
--- a/libc/private/bionic_auxv.h
+++ b/libc/private/bionic_auxv.h
@@ -29,6 +29,7 @@
 #define _PRIVATE_BIONIC_AUXV_H_
 
 #include <elf.h>
+#include <sys/cdefs.h>
 
 __BEGIN_DECLS
 
diff --git a/libc/private/bionic_futex.h b/libc/private/bionic_futex.h
index 6c7fdbe9e..69658b1e3 100644
--- a/libc/private/bionic_futex.h
+++ b/libc/private/bionic_futex.h
@@ -29,6 +29,7 @@
 #define _BIONIC_FUTEX_H
 
 #include <linux/futex.h>
+#include <sys/cdefs.h>
 
 __BEGIN_DECLS
 
diff --git a/libc/private/bionic_time.h b/libc/private/bionic_time.h
index 464ab0f32..7c80f5953 100644
--- a/libc/private/bionic_time.h
+++ b/libc/private/bionic_time.h
@@ -29,6 +29,7 @@
 #define _BIONIC_TIME_H
 
 #include <time.h>
+#include <sys/cdefs.h>
 
 __BEGIN_DECLS
 
diff --git a/libc/private/resolv_private.h b/libc/private/resolv_private.h
index 1c3c1a28c..0e799ca2f 100644
--- a/libc/private/resolv_private.h
+++ b/libc/private/resolv_private.h
@@ -54,6 +54,8 @@
 #ifndef _RESOLV_PRIVATE_H_
 #define	_RESOLV_PRIVATE_H_
 
+#include <sys/cdefs.h>
+
 #include <resolv.h>
 #include "resolv_static.h"
 #include <net/if.h>