Author: Dr. Werner Fink <werner@suse.de>

---
 texk/web2c/luatexdir/luaffi/ctype.c |    4 ++++
 texk/web2c/luatexdir/luaffi/ffi.h   |    2 +-
 2 files changed, 5 insertions(+), 1 deletion(-)

--- texk/web2c/luatexdir/luaffi/ctype.c
+++ texk/web2c/luatexdir/luaffi/ctype.c	2017-05-31 13:08:25.421741873 +0000
@@ -245,6 +245,10 @@ void* to_cdata(lua_State* L, int idx, st
 
     lua_pop(L, 1); /* mt */
     cd = (struct cdata*) lua_touserdata(L, idx);
+    if (!cd) {
+        lua_pushnil(L);
+        return NULL;
+    }
     *ct = cd->type;
     lua_getuservalue(L, idx);
 
--- texk/web2c/luatexdir/luaffi/ffi.h
+++ texk/web2c/luatexdir/luaffi/ffi.h	2017-06-01 09:12:45.128442092 +0000
@@ -370,7 +370,7 @@ __declspec(align(16))
 #endif
 struct cdata {
     const struct ctype type
-#ifdef __GNUC__
+#if 0 /* def __GNUC__ */
       __attribute__ ((aligned(16)))
 #endif
       ;