Previously the GN Windows build specified the symbol file $pdbfile but this variable was never defined, so the command like would just say "/Fd" and the default one would be used.
This patch defines some per-target variables in the ninja file for the toolchain to use. The Windows toolchain uses these to construct C- and C++-specific pdb files (the MS tools can't share between these two) for the current target.
BUG=
R=scottmg@chromium.org
Review URL: https://codereview.chromium.org/406453002
git-svn-id: http://src.chromium.org/svn/trunk/src/build@284137 4ff67af0-8c30-449e-8e8b-ad334ec8d88c