Backport patch to fix error check with access(3) failures

The code was not properly checking the failure from access(3).

Backport the patch from GitHub (made after the 0.4 release) which fixes this
issue.

Bump PORTREVISION for the change.

PR:		237459
Reviewed by:	asomers, jmmv
Approved by:	jmmv (maintainer)
Obtained from:	https://github.com/jmmv/lutok (a23c7b894cf50dea5e927e36a3578b720fffcf23)
Differential Revision: https://reviews.freebsd.org/D20002

devel/lutok/Makefile

@@ -3,7 +3,7 @@
 
 PORTNAME=	lutok
 PORTVERSION=	0.4
-PORTREVISION=	6
+PORTREVISION=	7
 CATEGORIES=	devel
 MASTER_SITES=	https://github.com/jmmv/lutok/releases/download/${PORTNAME}-${PORTVERSION}/ \
 		LOCAL/jmmv

devel/lutok/files/patch-state.cpp

@@ -0,0 +1,11 @@
+--- state.cpp.orig	2019-04-22 05:13:10 UTC
++++ state.cpp
+@@ -492,7 +492,7 @@ lutok::state::is_userdata(const int inde
+ void
+ lutok::state::load_file(const std::string& file)
+ {
+-    if (!::access(file.c_str(), R_OK) == 0)
++    if (::access(file.c_str(), R_OK) == -1)
+         throw lutok::file_not_found_error(file);
+     if (luaL_loadfile(_pimpl->lua_state, file.c_str()) != 0)
+         throw lutok::api_error::from_stack(*this, "luaL_loadfile");