[XRay] Detect terminfo library

Instead of assuming `-ltinfo` works, check whether there's terminfo
support on the host where LLVMSupport is compiled.

Follow-up to D52220.

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@342523 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed