lua5.1: fix broken source fetch (#40748)

The upstream src URL for the patch appears to no longer exist. Per discussion in
https://github.com/NixOS/nixpkgs/issues/39927, the upstream URL is not stable,
so this commit inlines the patch in the nixpkgs src tree.

pkgs/development/interpreters/lua-5/5.1.0004-Fix-stack-overflow-in-vararg-functions.patch

@@ -0,0 +1,21 @@
+From: Enrico Tassi <gareuselesinge@debian.org>
+Date: Tue, 26 Aug 2014 16:20:55 +0200
+Subject: Fix stack overflow in vararg functions
+
+---
+ src/ldo.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/src/ldo.c b/src/ldo.c
+index d1bf786..30333bf 100644
+--- a/src/ldo.c
++++ b/src/ldo.c
+@@ -274,7 +274,7 @@ int luaD_precall (lua_State *L, StkId func, int nresults) {
+     CallInfo *ci;
+     StkId st, base;
+     Proto *p = cl->p;
+-    luaD_checkstack(L, p->maxstacksize);
++    luaD_checkstack(L, p->maxstacksize + p->numparams);
+     func = restorestack(L, funcr);
+     if (!p->is_vararg) {  /* no varargs? */
+       base = func + 1;

pkgs/development/interpreters/lua-5/5.1.nix

@@ -20,12 +20,7 @@ stdenv.mkDerivation rec {
   buildInputs = [ readline ];
 
   patches = (if stdenv.isDarwin then [ ./5.1.darwin.patch ] else [ dsoPatch ])
-    ++ [(fetchpatch {
-      name = "CVE-2014-5461.patch";
-      url = "http://anonscm.debian.org/cgit/pkg-lua/lua5.1.git/plain/debian/patches/"
-        + "0004-Fix-stack-overflow-in-vararg-functions.patch?id=b75a2014db2ad65683521f7bb295bfa37b48b389";
-      sha256 = "05i5vh53d9i6dy11ibg9i9qpwz5hdm0s8bkx1d9cfcvy80cm4c7f";
-    })];
+    ++ [ ./5.1.0004-Fix-stack-overflow-in-vararg-functions.patch ];
 
   configurePhase =
     if stdenv.isDarwin