include: include vlc_threads.h when using vlc_global_lock()

include/vlc_avcodec.h

@@ -21,6 +21,8 @@
 #ifndef VLC_AVCODEC_H
 # define VLC_AVCODEC_H 1
 
+#include <vlc_threads.h>
+
 static inline void vlc_avcodec_lock (void)
 {
     vlc_global_lock (VLC_AVCODEC_MUTEX);

include/vlc_gcrypt.h

@@ -23,6 +23,7 @@
  * This file implements gcrypt support functions in vlc
  */
 
+#include <vlc_threads.h>
 #include <errno.h>
 
 static inline void vlc_gcrypt_init (void)

include/vlc_xlib.h

@@ -26,6 +26,8 @@
 # include <X11/Xlib.h>
 # include <X11/Xlibint.h>
 
+#include <vlc_threads.h>
+
 static inline bool vlc_xlib_init (vlc_object_t *obj)
 {
     if (!var_InheritBool (obj, "xlib"))