swift234

Revert "Add -linker-path frontend option to choose the linker"

This reverts commit 58cfa27eb5920aa281dbb381fa14bbd954679c17.

We require at least clang-3.6 for C++14 build support but
Ubuntu 14.04's clang-3.6 package does not lay down the symlink
/usr/bin/clang++ -> /usr/bin/clang++-3.6. We will require a
clang++ alternatives entry or symlink when building for these
systems (see README.md).