Remove LTO-related hacks from binutils build script. This effectively reverts: https://codereview.chromium.org/1330433002 (link against LLVM's libstdc++) https://codereview.chromium.org/1670073003 (link against tcmalloc) and part of https://codereview.chromium.org/899783003 (export plugin-api.h) All of which were to support use of LLVM's gold plugin for LTO. Because we no longer build or use the gold plugin, we no longer need this complexity in the build script. BUG=607968 [email protected] Review-Url: https://codereview.chromium.org/2961943002 Cr-Original-Commit-Position: refs/heads/master@{#483173} Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src Cr-Mirrored-Commit: effae3bbe9479ad36042df4b4a5db3dc3ebf0c41