add a dependency on terminfo library if llvm uses it
add a dependency on terminfo library if llvm uses it

Ncurses related symbols can either all be found in libnurses or split
between libncurses and libtinfo. The main LLVM cmake scripts look for the
setupterm symbol and stores the library that has it in TERMINFO_LIBS. This
covers the split and unified ncurses case. LLDB uses symbols that can end
up in libtinfo so this library should be pulled in if it is found.

There is still an exotic case left where LLDB is configured with
-DLLDB_DISABLE_CURSES=NO and LLVM with -DLLVM_ENABLE_TERMINFO=NO but
misconfigurations will always be possible. Possibly a diagnostic could be
added for that.

This fixes bug 24693.

Differential Revision: http://reviews.llvm.org/D12672
Patch by Jeremi Piotrowski

git-svn-id: 4c4cc70b1ef44ba2b7963015e681894188cea27e@247842 91177308-0d34-0410-b5e6-96231b3b80d8

apple/swift-lldb,apple/swift-lldb,llvm-mirror/lldb,apple/swift-lldb,llvm-mirror/lldb,apple/swift-lldb,llvm-mirror/lldb,apple/swift-lldb,llvm-mirror/lldb,llvm-mirror/lldb,apple/swift-lldb