[llvm] r241663 - Revert r241621, "[CMake] Cleanup tools/CMakeLists.txt to take advantage of the auto-registration that was already partially working."

[NAKAMURA Takumi]

Chris, thanks for your working.

2015-07-11 5:45 GMT+09:00 Chris Bieneman <beanz at apple.com>:
> Takumi,
>
> How does this sound. I’d like to re-land the patches with the following
> changes:
>
> (1) Keep the LLVM_EXTERNAL_*_SOURCE_DIR naming
> (2) Ignore LLVM_EXTERNAL_*_SOURCE_DIR if an in-tree directory exists
> (3) Only cache LLVM_EXTERNAL_*_SOURCE_DIR variables if they are used

Sounds good. For now, their default value may null.

> The patches will still:
> (1) Migrate to implicit adding tools by default
> (2) Use LLVM_TOOL_*_BUILD to enable and disable tool builds, and to prevent
> tools from being added more than once
> (3) Generate LLVM_TOOL_*_BUILD for all tools as advanced options

I am still uncomfortable about them. Even they were ADVANCED, they
might occupy many lines in ccmake (or cmake-gui)
and they would stay in the cache if they were removed again.
I don't imagine any usecases to toggle individual LLVM_TOOL_*_BUILD.

That said, it's ok as far as the tree is fine.