Big fixes in the cross build:

- Before this changes, cflags and ldflags for the native and the cross compiler
  got mixed. Not all the gcc-wrapper/gcc-cross-wrapper variables are
  independant now, but enough, I think.
- Fixed the generic stdenv expression, which did a big mess on buildInputs and
  buildNativeInputs. Now it distinguishes when there is a stdenvCross or not.
  Maybe we should have a single stdenv and forget about the stdenvCross
  adapter - this could end in a stdenv a bit complex, but simpler than the
  generic stdenv + adapter.
- Added basic support in pkgconfig for cross-builds: a single PKG_CONFIG_PATH
  now works for both the cross and the native compilers, but I think this
  should work well for most cases I can think of.
- I tried to fix the guile expression to cross-biuld; guile is built, but not
  its manual, so the derivation still fails. Guile requires patching to
  cross-build, as far as I understnad.
- Made the glibcCross build to be done through the usage of a
  gcc-cross-wrapper over the gcc-cross-stage-static, instead of using it
  directly.
- Trying to make physfs (a neverball dependency) cross build.
- Updated the gcc expression to support building a cross compiler without getting
  derivation variables mixed with those of the stdenvCross.

svn path=/nixpkgs/branches/stdenv-updates/; revision=18534

pkgs/development/interpreters/guile/default.nix

@@ -9,19 +9,26 @@ stdenv.mkDerivation rec {
   };
 
   buildNativeInputs = [ makeWrapper ];
-  propagatedBuildInputs = [ libtool gmp ];
-  propagatedBuildNativeInputs = [readline gawk];
+  buildInputs = [ libtool ];
+  propagatedBuildInputs = [ readline gmp libtool ];
+  propagatedBuildNativeInputs = [ gawk ];
 
   postInstall = ''
     wrapProgram $out/bin/guile-snarf --prefix PATH : "${gawk}/bin"
   '';
 
-  NIX_DEBUG=1;
-
   preBuild = ''
     sed -e '/lt_dlinit/a  lt_dladdsearchdir("'$out/lib'");' -i libguile/dynl.c
   '';
 
+  # Guile needs patching to preset results for the configure tests
+  # about pthreads, which work only in native builds.
+  preConfigure = ''
+    if test -n "$crossConfig"; then
+      configureFlags="--with-threads=no $configureFlags"
+    fi
+  '';
+
   doCheck = true;
 
   setupHook = ./setup-hook.sh;