Update tooltool manifest for macosx with a custom build of rustc 1.4.0
with --enable-rpath --disable-elf-tls and MACOSX_DEPLOYMENT_TARGET=10.7
on MacOS X 10.10.5, Xcode 7.1.1 (clang-700.1.76).
Built for x86_64-apple-darwin with the rustlib from a separate
i686-apple-darwin build copied into the tree to support 32-bit cross
for universal builds.
Since we've enabled rpath, we can drop the DYLD_LIBRARY_PATH setting
from mozconfig.rust. This method seems cleaner since the add/append
decision for DYLD_LIBRARY_PATH is verbose in shell.
91fa64f387