dtool/Config.cmake: Add missing empty option to BUILD_IPHONE.
Config.cmake: Add X11 location and option.
Add additional output, CG_LIBRARIES, to FindCg.cmake.
In CMake builds, link glgsg with CG_LIBRARIES.
Add header to CMake panda/metalibs/pandagl that causes an error when it is being built without proper support.
In CMake builds, link gobj with Squish (when enabled).
In CMake builds, link panda/express with Tar (when enabled).
Merge pull request #2 from kestred/config.cmake

Config.cmake