Add unittest for 'LD' in 'make_global_settings'

This CL describes the current behavior with some unittests, before making Ninja generator aware of 'LD' in 'make_global_settings'. See gyp r1931 for the background.

BUG=gyp:434
TEST=unittest
R=scottmg@chromium.org

Review URL: https://codereview.chromium.org/322973006

git-svn-id: http://gyp.googlecode.com/svn/trunk@1937 78cadc50-ecff-11dd-a971-7dbc132099af
2 files changed