Fix MSVC build

Added _WIN32 guards to new platform features. Using correct SetErrorStringWithFormat within Host when LLDB_DISABLE_POSIX is defined. Also fixed an if defined block.

llvm-svn: 195766
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServer.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServer.cpp
index 1e9bf0d..7cc3a05 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServer.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServer.cpp
@@ -1011,9 +1011,14 @@
     packet.GetHexByteString(path);
     if (m_is_platform)
     {
+#ifdef _WIN32
+        // Not implemented on Windows
+        return SendUnimplementedResponse("GDBRemoteCommunicationServer::Handle_QSetWorkingDir unimplemented");
+#else
         // If this packet is sent to a platform, then change the current working directory
         if (::chdir(path.c_str()) != 0)
             return SendErrorResponse(errno);
+#endif
     }
     else
     {