Autogen: Prepend instead of append `mocs_compilation.cpp` to the sources list

`mocs_compilation.cpp` easily takes a long time to compile when it
contains multiple `moc` files.  When it was appended like before
we ran into the situation that all smaller sources were already compiled when
`mocs_compilation.cpp` got compiled at last.  In that case a single core was
busy but all remaining cores stayed idle.

To optimize CPU core utilization we now prepend `mocs_compilation.cpp`
to the sources list instead of appending it.  This allows smaller source files
to get compiled *while* the long lasting `mocs_compilation.cpp` gets compiled.

Closes #18793

1 files changed, 2 insertions, 1 deletions

diff --git a/Source/cmQtAutoGenInitializer.h b/Source/cmQtAutoGenInitializer.h
index 47f157c..eefbaf0 100644
--- a/Source/cmQtAutoGenInitializer.h
+++ b/Source/cmQtAutoGenInitializer.h
@@ -102,7 +102,8 @@ private:
   bool SetupWriteAutogenInfo();
   bool SetupWriteRccInfo();
 
-  void AddGeneratedSource(std::string const& filename, GeneratorT genType);
+  void AddGeneratedSource(std::string const& filename, GeneratorT genType,
+                          bool prepend = false);
 
   bool GetMocExecutable();
   bool GetUicExecutable();