Summary:
The new function sys::path::user_cache_directory tries to discover
a directory suitable for cache storage for current system user.
On Windows and Darwin it returns a path to system-specific user cache directory.
On Linux it follows XDG Base Directory Specification, what is:
- use non-empty $XDG_CACHE_HOME env var,
- use $HOME/.cache.
Reviewers: chapuni, aaron.ballman, rafael
Subscribers: rafael, aaron.ballman, llvm-commits
Differential Revision: http://reviews.llvm.org/D13801
llvm-svn: 251784
0e97e5cb19