test-capi.nix: Add basic of C-API linkage

Downloads the 'lpty' library, builds it with LuaJIT, links it into
RaptorJIT.

default.nix

@@ -18,6 +18,7 @@ let
   raptorjit-assert = raptorjit.overrideAttrs(
                        old: { NIX_CFLAGS_COMPILE = " -DLUA_USE_ASSERT"; });
   test = name: args: (callPackage ./test.nix { inherit name args; raptorjit = raptorjit-assert; });
+  test-capi = callPackage ./test-capi.nix { inherit pkgs raptorjit; };
   check-generated-code = (callPackage ./check-generated-code.nix { inherit raptorjit; });
   nowarnings = raptorjit.overrideAttrs(
                  old: { NIX_CFLAGS_COMPILE = "-Werror"; });
@@ -30,6 +31,7 @@ in
   test-O2    = test "O2"    "-O2";
   test-O1    = test "O1"    "-O1";
   test-nojit = test "nojit" "-joff";
+  test-capi  = test-capi;
   # Test that generated bytecode is compatible
   test-bytecode-compat = pkgs.runCommand "test-bytecode-compat"
                                            { buildInputs = [ raptorjit ]; }

test-capi.nix

@@ -0,0 +1,21 @@
+{ pkgs, raptorjit, ... }:
+with pkgs;
+
+let lpty =
+  fetchurl rec {
+    url = "http://tset.de/downloads/lpty-1.2.2-1.tar.gz";
+    sha256 = "071mvz79wi9vr6hvrnb1rv19lqp1bh2fi742zkpv2sm1r9gy5rav";
+  };
+in
+
+stdenv.mkDerivation {
+  name = "test-capi";
+  src = lpty;
+  phases = "unpackPhase buildPhase testPhase";
+  buildInputs = [ luajit raptorjit which ];
+  testPhase = ''
+    ${raptorjit}/bin/raptorjit -e 'require "lpty"  print("Successfully loaded a C library.")' \
+      > $out
+  '';
+}
+