YouCompleteMe needs the packages to be available in ycmd's third_party
directory, and things start getting pretty complicated when we try to
use our package libs instead of the vendored ones. We can revisit this
at a later time, but we'll need to ensure that we don't break the vim
plugin.
Tested in vim.
This also fixes build for Mac OS X. The build failed before because both
clang and clang-unwrapped were in scope and CMake tried to compile the
library with unwrapped clang with well-understood consequences.
This commit fixes the issue by passing libclang through a different way.
Daiderd Jordan
Charles Strahan
Frederik Rietdijk
Alexey Shmalko
Tuomas Tynkkynen