HDCTOOLS: Better dealing with differences between host OS types

Details

  This change removes the conditional code in 'c.mk' and makes it
  easier to reason about by having all host-os-specific code in a file
  associated with that host OS.

  In other words, all settings for Mac are now in a single file, and
  all settings for Linux are in a single file.

  There are several advantages to this:

    o No conditionals to muddle the Makefile.

    o No changes to the Linux build will affect the Mac, and no
      changes to the Mac will affect the Linux build (in general).

    o Easier, if ever needed, to add support for a new host OS.

Testing

  Built product on Linux.
  No semantic changes.

BUG=none
TEST=See above.

Change-Id: I3b977ef936c83d9fd627873a179bdba045cd72f1
Signed-off-by: Taylor Hutt <thutt@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/11955
Reviewed-by: Terry Lambert <tlambert@chromium.org>
Reviewed-by: Todd Broch <tbroch@chromium.org>
3 files changed