qmake: Introduce compile_included_sources CONFIG option

By default, qmake does not compile source files that are included in
other source files. The new CONFIG option compile_included_sources
disables this behavior.

Pick-to: 5.15
Fixes: QTBUG-90801
Change-Id: I60c997938895f3a743d32ea385efdbe6bcf315bb
Reviewed-by: Kai Koehne <kai.koehne@qt.io>

qmake/doc/src/qmake-manual.qdoc

@@ -1248,6 +1248,9 @@
             subproject.
     \row \li no_include_pwd \li Do not add the current directory to
             INCLUDEPATHS.
+    \row \li compile_included_sources \li By default, qmake does not
+             compile source files that are included in other source files. This
+             option disables this behavior.
     \endtable
 
     When you use the \c debug_and_release option (which is the default under

qmake/generators/makefile.cpp

@@ -943,6 +943,15 @@ MakefileGenerator::filterIncludedFiles(const char *var)
     inputs.removeIf(isIncluded);
 }
 
+void MakefileGenerator::processSources()
+{
+    if (project->isActiveConfig("compile_included_sources"))
+        return;
+
+    filterIncludedFiles("SOURCES");
+    filterIncludedFiles("GENERATED_SOURCES");
+}
+
 static QString
 qv(const ProString &val)
 {

qmake/generators/makefile.h

@@ -201,10 +201,7 @@ protected:
     virtual bool doDepends() const { return Option::mkfile::do_deps; }
 
     void filterIncludedFiles(const char *);
-    void processSources() {
+    void processSources();
-        filterIncludedFiles("SOURCES");
-        filterIncludedFiles("GENERATED_SOURCES");
-    }
 
     //for installs
     virtual QString defaultInstall(const QString &);