CMake build: Disable FakeVim and building with PCH with Qt 6

FakeVim does not compile on MSVC because Qt 6 doesn't like
meta types that are recursive maps with keys that have a custom
operator==.
Building with PCH has different issues on macOS and MSVC.

Change-Id: Id1b9580f7347f1c8facade67fd74532a023af41f
Reviewed-by: Alessandro Portale <alessandro.portale@qt.io>
Reviewed-by: hjk <hjk@qt.io>

CMakeLists.txt

@@ -25,7 +25,6 @@ set(CMAKE_CXX_EXTENSIONS OFF)
 option(WITH_TESTS "Build Tests" OFF)
 add_feature_info("Build tests" ${WITH_TESTS} "")
 option(WITH_DEBUG_CMAKE "Enabled CMake project debugging functionality (e.g. source file disk checking)" OFF)
-option(BUILD_WITH_PCH "Build with precompiled headers" ON)
 
 # merge binary directories of sub projects into top level
 set(QTC_MERGE_BINARY_DIR ON)
@@ -50,10 +49,15 @@ find_package(Qt5
 )
 if (Qt5_VERSION VERSION_LESS 6.0.0)
   install(TARGETS Qt6Core5Compat EXPORT QtCreator)
+  set(BUILD_WITH_PCH_DEFAULT ON)
+else()
+  set(BUILD_WITH_PCH_DEFAULT OFF)
 endif()
 find_package(Qt5 COMPONENTS LinguistTools QUIET)
 find_package(Qt5 COMPONENTS Designer DesignerComponents Help SerialPort Svg Tools QUIET)
 
+option(BUILD_WITH_PCH "Build with precompiled headers" ${BUILD_WITH_PCH_DEFAULT})
+
 find_package(Threads)
 find_package(Clang QUIET)
 find_package(KF5SyntaxHighlighting QUIET)

src/plugins/fakevim/CMakeLists.txt

@@ -1,4 +1,5 @@
 add_qtc_plugin(FakeVim
+  CONDITION Qt5_VERSION VERSION_LESS 6.0.0
   PLUGIN_DEPENDS Core TextEditor
   PLUGIN_TEST_DEPENDS CppEditor CppTools
   SOURCES ${TEST_SOURCES}