Add includemocs.py and create one moc file per cpp file

[m-kuhn]

This creates an include moc file per source file, which is supposed to improve build times for incremental builds and have a few other positive effects.
https://planet.kde.org/friedrich-kossebau-2023-06-28-include-also-moc-files-of-headers/
It should also help to fix the requirement for /bigobj in some environments (not sure about the exact conditions under which this is required)

Copied from https://github.com/KDABLabs/KDToolBox/tree/master/qt/includemocs

Fixes #59157

What this does (reviewer guide)

1. adds a helper script scripts/includemocs.py which can add moc include lines and detect missing ones (see link above for source)
2. add moc include lines (that's where all the files are affected)
3. adds include guards in various header files where they were missing
4. removes unused private variables
5. removes qt_add_cpp calls, they are not needed with automoc in place

[m-kuhn]

To reduce deviation from master and make future backporting easier, I'd propose to backport this too.

[m-kuhn]

Nice addition, for whatever reason, we now get warnings about unused private variables which were hidden before.

[github-actions]

🪟 Windows builds

Download Windows builds of this PR for testing.
Debug symbols for this build are available here.
(Built from commit 3a7182b)

🪟 Windows Qt6 builds

Download Windows Qt6 builds of this PR for testing.
(Built from commit 3a7182b)

[nyalldawson]

Lgtm! will you resurrect the warnings as Error flag?

[m-kuhn]

Lgtm! will you resurrect the warnings as Error flag?

Thanks for the review @nyalldawson
It's gone

[nicogodet]

@m-kuhn It still fails on my machine
D:\QGIS_src\src\core\expression\qgsexpressionfunction.cpp : fatal error C1128: le nombre de sections a dépassé la limite du format de fichier objet : compilez avec /bigobj
Same point as before

I compile with Ninja and ccache, should I delete my build folder and retry ?
Ninja compiles more than 3000 files so I suspect it will not change the outcome

[m-kuhn]

That's on a different file now (not the moc any more)

Can you add this file to the list that you cited before:

QGIS/src/core/CMakeLists.txt

Lines 2183 to 2189 in 42a3bcf

	if(MSVC)
	set_source_files_properties(
	${CMAKE_CURRENT_BINARY_DIR}/qgsexpression_texts.cpp
	${CMAKE_CURRENT_BINARY_DIR}/qgis_core_autogen/mocs_compilation.cpp
	proj/qgscoordinatereferencesystem.cpp
	PROPERTIES COMPILE_FLAGS "/bigobj"
	)

[nicogodet]

diff --git a/src/app/CMakeLists.txt b/src/app/CMakeLists.txt
index f64c6e76cb1..ed2f1ae7765 100644
--- a/src/app/CMakeLists.txt
+++ b/src/app/CMakeLists.txt
@@ -477,16 +477,21 @@ if(PEDANTIC)
 endif()

 if(MSVC)
-# -wd4091 Avoid 'typedef' ignored on left of '' when no variable is declared warning in dbghelp.h
-set_source_files_properties(
-  qgisapp.cpp
-  main.cpp
-  qgscrashhandler.cpp
-  PROPERTIES COMPILE_FLAGS -wd4091)
+  # -wd4091 Avoid 'typedef' ignored on left of '' when no variable is declared warning in dbghelp.h
+  set_source_files_properties(
+    qgisapp.cpp
+    main.cpp
+    qgscrashhandler.cpp
+    PROPERTIES COMPILE_FLAGS -wd4091
+  )
+  set_source_files_properties(
+    qgisapp.cpp
+    PROPERTIES COMPILE_FLAGS "/bigobj"
+  )
 endif()

 if(HAVE_OPENCL)
-    include_directories(SYSTEM ${OpenCL_INCLUDE_DIRS})
+   include_directories(SYSTEM ${OpenCL_INCLUDE_DIRS})
 endif()

 if(ENABLE_MODELTEST)

diff --git a/src/core/CMakeLists.txt b/src/core/CMakeLists.txt
index 808540650d2..0c1ad171c11 100644
--- a/src/core/CMakeLists.txt
+++ b/src/core/CMakeLists.txt
@@ -2183,7 +2183,9 @@ endif()
 if(MSVC)
   set_source_files_properties(
       ${CMAKE_CURRENT_BINARY_DIR}/qgsexpression_texts.cpp
+      expression/qgsexpressionfunction.cpp
+      textrenderer/qgsfontmanager.cpp
       proj/qgscoordinatereferencesystem.cpp
       PROPERTIES COMPILE_FLAGS "/bigobj"
   )

It builds with theses diffs
I can push them (with or without little formatting)

[m-kuhn]

Please do (with or without formatting)