warning cleanup (use LLDB_INVALID_HOST_THREAD instead of NULL)

git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@189393 91177308-0d34-0410-b5e6-96231b3b80d8
Moved the static s_regex into a function body to allow it to be lazily initialized when/if it is ever used. We try to avoid global constructors when building shared libraries on Darwin.



git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@189397 91177308-0d34-0410-b5e6-96231b3b80d8