Enable lldb-server on Windows

Summary:
This commit contains three small changes to enable lldb-server on Windows.

- Add lldb-server for Windows to the build
- Disable pty redirection on Windows for the initial lldb-server bring up
- Add a support to get the parent pid for a process on Windows
- Ifdef some signals which aren't supported on Windows

Thanks to Hui Huang for the help with this patch!

Reviewers: labath

Reviewed By: labath

Subscribers: JDevlieghere, compnerd, Hui, amccarth, xiaobai, srhines, mgorny, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D61686

llvm-svn: 368774
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp
index 24a0991..b447203 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp
@@ -39,6 +39,8 @@
 
 #if defined(__APPLE__)
 #define DEBUGSERVER_BASENAME "debugserver"
+#elif defined(_WIN32)
+#define DEBUGSERVER_BASENAME "lldb-server.exe"
 #else
 #define DEBUGSERVER_BASENAME "lldb-server"
 #endif