Need to build gwt.

Index: src/CMakeLists.txt
--- src/CMakeLists.txt.orig
+++ src/CMakeLists.txt
@@ -18,11 +18,7 @@ cmake_minimum_required(VERSION 3.4.3)
 # we've already got it from the 64-bit build), for development mode
 # (since we'll want to build it incrementally using superdevmode),
 # or when building monitor only
-if ( (NOT RSTUDIO_SESSION_WIN32) AND
-     (NOT RSTUDIO_DEVELOPMENT) AND
-     (NOT RSTUDIO_CONFIG_MONITOR_ONLY) )
-   add_subdirectory(gwt)
-endif()
+add_subdirectory(gwt)
 
 add_subdirectory(cpp)