tree c85f3131e225f5e36dc9af3271cdee5003dc6567
parent 51bd3fa0b2c1c1fb861ea6ae4b113f7961fdd3a2
author Ying Wang <wangying@google.com> 1326415097 -0800
committer Ying Wang <wangying@google.com> 1326415097 -0800

Compute TARGET_TOOLCHAIN_ROOT from TARGET_TOOLS_PREFIX.

Sometimes TARGET_TOOLS_PREFIX is passed in as command line makefile
variable or environmental variable without TARGET_TOOLCHAIN_ROOT.
This change computes TARGET_TOOLCHAIN_ROOT from TARGET_TOOLS_PREFIX in
that case.

Change-Id: I0a37dc1f4d1e3e1951faeffd5e9f926f0a6614dd