GCC 4.5: Fix the `GLIBC_DYNAMIC_LINKER' macro on NixOS and in cross builds.
GCC 4.5: Fix the `GLIBC_DYNAMIC_LINKER' macro on NixOS and in cross builds.

Among others, this should fix the dynamic linker path reported by
"gcc --help --verbose".

svn path=/nixpkgs/branches/stdenv-updates/; revision=25131

NixOS/nixpkgs,triton/triton,triton/triton,triton/triton,SymbiFlow/nixpkgs,SymbiFlow/nixpkgs,triton/triton,SymbiFlow/nixpkgs,NixOS/nixpkgs,SymbiFlow/nixpkgs,NixOS/nixpkgs,triton/triton,SymbiFlow/nixpkgs,triton/triton,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,SymbiFlow/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,SymbiFlow/nixpkgs,NixOS/nixpkgs,SymbiFlow/nixpkgs,SymbiFlow/nixpkgs,NixOS/nixpkgs,triton/triton,NixOS/nixpkgs,NixOS/nixpkgs,triton/triton,SymbiFlow/nixpkgs,SymbiFlow/nixpkgs,SymbiFlow/nixpkgs,SymbiFlow/nixpkgs,NixOS/nixpkgs