Add dependencies_stb_dir variable for STB directory.
Add dependencies_stb_dir variable for STB directory.

- And reorder entries in alphabetical order.

Change-Id: Ic09a86be8ad934713098cb7e5b86d60b5806749b
Tested: on OSX.

google/fplutil,google/fplutil,google/fplutil,google/fplutil,google/fplutil,google/fplutil