[clang-tidy] add option to specify build path
[clang-tidy] add option to specify build path

Summary:
compile_commands.json is usually generated in the build directory.
Projects like LLVM/Clang enforce out-of-source builds.
This option allow allow such projects to work out of the box, without
moving the compilation database manually.

The naming of the option is similar to the one use by other tools:

    clang-{check,modernize,query,rename,tidy} -p=<build_path> <...>

Reviewers: alexfh

Differential Revision: http://reviews.llvm.org/D13199

git-svn-id: a34e9779ed74578ad5922b3306b3d80a0c825546@248723 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/clang-tools-extra,llvm-mirror/clang-tools-extra,llvm-mirror/clang-tools-extra,llvm-mirror/clang-tools-extra