CMake: Fix missing resources in Windows debug DLLs/EXEs

When configuring a Windows build with NMC and
"CMAKE_CONFIGURATION_TYPES=Release;Debug", then with CMake 3.18.4 only
the targets of the main configuration would get the version resource
compiled in.

With 3.19.0 RC 2 the problem cannot be observed.

Work-around the issue by revisiting our work-around of another CMake
issue: use just one object library per target to embed win32 resources.
This works with both tested CMake versions and seems cleaner anyways.

Fixes: QTBUG-88267
Change-Id: I20f596ab669ae716c330d7aa60aa717b9e3e4aa7
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>

src/corelib/Qt6CoreMacros.cmake

@@ -1023,6 +1023,13 @@ END
             set(cfgs "${CMAKE_BUILD_TYPE}")
             set(outputs "${rc_file_output}")
         endif()
+
+        # We would like to do the following:
+        #     target_sources(${target} PRIVATE "$<$<CONFIG:${cfg}>:${output}>")
+        # However, https://gitlab.kitware.com/cmake/cmake/-/issues/20682 doesn't let us.
+        # Work-around by compiling the resources in an object lib and linking that.
+        add_library(${target}_rc OBJECT "${output}")
+        target_link_libraries(${target} PRIVATE $<TARGET_OBJECTS:${target}_rc>)
         while(outputs)
             list(POP_FRONT cfgs cfg)
             list(POP_FRONT outputs output)
@@ -1031,12 +1038,7 @@ END
                 DEPENDS "${input}"
                 COMMAND ${CMAKE_COMMAND} -E copy_if_different "${input}" "${output}"
             )
-
+            target_sources(${target}_rc PRIVATE "$<$<CONFIG:${cfg}>:${output}>")
-            # We would like to do the following:
-            #     target_sources(${target} PRIVATE "$<$<CONFIG:${cfg}>:${output}>")
-            # However, https://gitlab.kitware.com/cmake/cmake/-/issues/20682 doesn't let us.
-            add_library(${target}_${cfg}_rc OBJECT "${output}")
-            target_link_libraries(${target} PRIVATE "$<$<CONFIG:${cfg}>:${target}_${cfg}_rc>")
         endwhile()
     endif()
 endfunction()