Overriding linker path

[cmarcelo]

Is there a way to override the linker path to use something other than "/usr/bin/ld"?

Context: trying to get circle working in NixOS, which keeps packages all separated from each other, so there's a directory for each of gcc (which includes libstdc++), glibc and binutils. Because they are all split, --gcc-toolchain option isn't sufficient.