Remove all checking for the various terminfo headers (term.h and
curses.h). Finding these headers is next to impossible. For example, on
Debian systems libtinfo-dev provides the terminfo reading library we
want, but *not* term.h. For the header, you have to use libncurses-dev.
And libncursesw-dev provides a *different* term.h in a different
location!

These headers aren't worth it. We want two functions the signatures of
which are clearly spec'ed in sys-v and other documentation. Just declare
them ourselves and call them. This should fix some debian builders and
provide better support for "minimal" debian systems that do want color
autodetection.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188165 91177308-0d34-0410-b5e6-96231b3b80d8