Linux: Handle GYP_DEFINES="host_arch=x86_64" in third_party/binutils/download.py.

BUG=368544
NOTRY=true
TBR=thakis@chromium.org

Review URL: https://codereview.chromium.org/263483003

Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 04ddc345ce9cfa8e19cc36a9c3913eea194c2984
1 file changed