Ensure header files using __BEGIN_DECLS include sys/cdefs.h.

We keep fixing these one-by-one; let's fix them all at once.

Found thus:

  find . -name *.h | xargs grep -L sys/cdefs.h | xargs grep -l BEGIN_DECL | xargs grep -L sys/types

Change-Id: I188842aa2484dc6176e96556d57c38a0f785b59b

libc/bionic/pthread_internal.h

@@ -30,6 +30,7 @@
 
 #include <pthread.h>
 #include <stdbool.h>
+#include <sys/cdefs.h>
 
 __BEGIN_DECLS
 

libc/include/mntent.h

@@ -29,6 +29,7 @@
 #define _MNTENT_H_
 
 #include <stdio.h>
+#include <sys/cdefs.h>
 
 #define MNTTYPE_IGNORE "ignore"
 

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
 

libc/include/sys/auxv.h

@@ -29,6 +29,7 @@
 #define _SYS_AUXV_H_
 
 #include <linux/auxvec.h>
+#include <sys/cdefs.h>
 
 __BEGIN_DECLS
 

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
 

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

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

libc/private/bionic_auxv.h

@@ -29,6 +29,7 @@
 #define _PRIVATE_BIONIC_AUXV_H_
 
 #include <elf.h>
+#include <sys/cdefs.h>
 
 __BEGIN_DECLS
 

libc/private/bionic_futex.h

@@ -29,6 +29,7 @@
 #define _BIONIC_FUTEX_H
 
 #include <linux/futex.h>
+#include <sys/cdefs.h>
 
 __BEGIN_DECLS
 

libc/private/bionic_time.h

@@ -29,6 +29,7 @@
 #define _BIONIC_TIME_H
 
 #include <time.h>
+#include <sys/cdefs.h>
 
 __BEGIN_DECLS
 

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"