missing from actions.c, read_fs.c, sort.c 

Index: squashfs-tools/mksquashfs.h
--- squashfs-tools/mksquashfs.h.orig
+++ squashfs-tools/mksquashfs.h
@@ -24,6 +24,7 @@
  * mksquashfs.h
  *
  */
+#include <pthread.h>
 
 struct dir_info {
 	char			*pathname;