Enable lldb-gdbserver on Linux as well in the cmake build


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@200870 91177308-0d34-0410-b5e6-96231b3b80d8
Enable lldb-gdbserver for FreeBSD in the (g)make build


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@200871 91177308-0d34-0410-b5e6-96231b3b80d8