Adding a new version of the gcc-wrapper, named gcc-wrapper2, in order not to rebuild

stdenv.

In this gcc-wrapper2 I made the ld-wrapper.sh to handle the linking with shared
objects through direct pass as ld command arguments of the absolute path to shared
objects, instead of using the -L/-l combinations.

cmake 'FindXXX.cmake' modules make a strong usage of the dynamic linking directly
passing the absolute path to the shared object to the linker, and as our wrapper did
not add any -rpath for those, writting the nix expressions for some cmake packages
resulted in a lot of tricks, compared to using this gcc-wrapper2.

This gcc-wrapper2/ld-wrapper.sh should become the gcc-wrapper/ld-wrapper in a
stdenv update.

I also updated some cmake expressions to use this gcc-wrapper2, and reduced its
tricks.

I also updated the cmake setup-hook for it to make cmake not touch any rpath decided
at build time, when running the 'make install' of makefiles created by cmake.

svn path=/nixpkgs/trunk/; revision=18885

pkgs/applications/video/avidemux/default.nix

@@ -18,11 +18,9 @@ stdenv.mkDerivation {
 
   cmakeFlags = "-DPTHREAD_INCLUDE_DIR=${stdenv.glibc}/include" +
     " -DGETTEXT_INCLUDE_DIR=${gettext}/include" +
-    " -DSDL_INCLUDE_DIR=${SDL}/include/SDL" +
-    " -DCMAKE_SKIP_BUILD_RPATH=ON" +
-    " -DCMAKE_BUILD_TYPE=Release";
+    " -DSDL_INCLUDE_DIR=${SDL}/include/SDL";
 
-  NIX_LDFLAGS="-lxml2 -lXv -lSDL -lQtGui -lQtCore -lpthread";
+  NIX_LDFLAGS="-lpthread";
 
   postInstall = ''
     cd $NIX_BUILD_TOP/$sourceRoot