Make FSUIPC optional

Summary:
If FSUIPC is configured, its support will be enabled in swift
and disabled otherwise.

Ref T91

Reviewers: #swift_pilot_client, msutcliffe

Reviewed By: #swift_pilot_client, msutcliffe

Subscribers: msutcliffe, jenkins, kbasan

Maniphest Tasks: T91

Differential Revision: https://dev.swift-project.org/D28

src/blackconfig/buildconfig.h

@@ -41,6 +41,9 @@ namespace BlackConfig
         //! with P3D support?
         static bool isCompiledWithP3DSupport(); // defined in buildconfig_gen.cpp.in
 
+        //! with Fsuipc support?
+        static bool isCompiledWithFsuipcSupport(); // defined in buildconfig_gen.cpp.in
+
         //! Compiled with any MS Flight Simulator support (P3D, FSX, FS9)
         static bool isCompiledWithMsFlightSimulatorSupport();