It's now the default. /cc #19456
This makes a real build simplification, because in our current
bootstrapping+aliases, `gcc6` attribute is not the default compiler
but a derivation *built by* the default compiler.
nix-exec didn't build before this commit already
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
