Patch from Firefox ESR 38 Void packaging.
--- mozilla/xpcom/io/nsLocalFileUnix.cpp.orig
+++ mozilla/xpcom/io/nsLocalFileUnix.cpp
@@ -28,6 +28,7 @@
 #define USE_LINUX_QUOTACTL
 #include <sys/mount.h>
 #include <sys/quota.h>
+#include <linux/fs.h>
 #endif
 
 #include "xpcom-private.h"
