* We also only use GIT_COMMIT_HASH where necessary to avoid rebuilding many
files for no reason, including splitting version.cpp out into a separate
project as we do with VS since otherwise changing its preprocessor defines
rebuilds the whole renderdoc project.
* At the same time, move the git hash to be internal only so we don't have to
try to link version.cpp into other projects like renderdoccmd or qrenderdoc.
baldurk
38f0d27901