LLVM_BUILD_TOOLS is a boolean variable that controls whether or not generated
targets for llvm tools are built by the "all" target. CLANG_BUILD_TOOLS is an
analogous variable for clang targets.
This is useful functionality for selectively disabling the building of clang
targets by default to speed up builds.
In terms of implementation, I just followed the model of LLVM's implementation
of this functionality.
llvm-svn: 275006
This matches how LLVM has its cmake files organized and is cleaner than just
shoving this business logic into the main CMakeLists.txt.
llvm-svn: 274992