qmake/xcode: Do not create OBJECTS_DIR

If we create OBJECTS_DIR at qmake time, Xcode will not consider this
directory as created by the build system, and "xcodebuild --clean" will
fail.

Prevent qmake from creating that directory in the Xcode generator.

Pick-to: 5.15 6.2
Fixes: QTBUG-96305
Change-Id: I874bf34a4289ce5f2d3e2ce070ffbe56d5368861
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>

qmake/generators/mac/pbuilder_pbx.cpp

@@ -2073,4 +2073,10 @@ ProjectBuilderMakefileGenerator::writeSettings(const QString &var, const ProStri
     return ret;
 }
 
+bool
+ProjectBuilderMakefileGenerator::inhibitMakeDirOutPath(const ProKey &path) const
+{
+    return path == "OBJECTS_DIR";
+}
+
 QT_END_NAMESPACE

qmake/generators/mac/pbuilder_pbx.h

@@ -66,6 +66,7 @@ public:
 protected:
     bool doPrecompiledHeaders() const override { return false; }
     bool doDepends() const override { return writingUnixMakefileGenerator && UnixMakefileGenerator::doDepends(); }
+    bool inhibitMakeDirOutPath(const ProKey &path) const override;
 };
 QT_END_NAMESPACE
 

qmake/generators/makefile.cpp

@@ -173,6 +173,9 @@ MakefileGenerator::initOutPaths()
         if (noIO() || (project->first("TEMPLATE") == "subdirs"))
             continue;
 
+        if (inhibitMakeDirOutPath(dkey))
+            continue;
+
         QString path = project->first(dkey).toQString(); //not to be changed any further
         path = fileFixify(path, FileFixifyBackwards);
         debug_msg(3, "Fixed output_dir %s (%s) into %s", dirs[x],
@@ -216,6 +219,18 @@ MakefileGenerator::initOutPaths()
     }
 }
 
+/*
+ * For the given directory path, return true if MakefileGenerator::initOutPaths() should inhibit the
+ * creation of the directory. Overload this in subclasses.
+ */
+bool
+MakefileGenerator::inhibitMakeDirOutPath(const ProKey &path) const
+{
+    Q_UNUSED(path);
+    return false;
+}
+
+
 QMakeProject
 *MakefileGenerator::projectFile() const
 {

qmake/generators/makefile.h

@@ -160,6 +160,7 @@ protected:
     void verifyCompilers();
     virtual void init();
     void initOutPaths();
+    virtual bool inhibitMakeDirOutPath(const ProKey &path) const;
     struct Compiler
     {
         QString variable_in;