Fix configure & qmake compilation with a future MSVC version

When MSVC supports ref-qualified members, we need to ensure that
qstring_compat.cpp can see the non-qualified definitions in qstring.h,
which means no precompiled header.

Alternatively, for a bootstrapped build we could not compile
qstring_compat.cpp or #ifndef the functions.

Change-Id: I8ece34503060f0b4b0f8f2df2fb9b0fb1311e269
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>

qmake/Makefile.win32

@@ -219,3 +219,7 @@ qmake_pch.obj:
 
 {$(SOURCE_PATH)\tools\shared\windows}.cpp{}.obj::
 	$(CXX) $(CXXFLAGS) $<
+
+# Make sure qstring_compat.obj isn't compiled with PCH enabled
+qstring_compat.obj: $(SOURCE_PATH)\src\corelib\tools\qstring_compat.cpp
+	$(CXX) -c $(CXXFLAGS_BARE) $(SOURCE_PATH)\src\corelib\tools\qstring_compat.cpp

src/corelib/tools/qstring_compat.cpp

@@ -39,9 +39,8 @@
 **
 ****************************************************************************/
 
-#if defined(QSTRING_H) && !defined(QT_BOOTSTRAPPED)
+#if defined(QSTRING_H)
 #  error "This file cannot be compiled with pre-compiled headers"
-//       (unless it's configure.exe, which is bootstrapped)
 #endif
 #define QT_COMPILING_QSTRING_COMPAT_CPP
 

tools/configure/Makefile.mingw

@@ -118,6 +118,10 @@ configureapp.o: $(CONFSRC)/configureapp.h $(CONFSRC)/environment.h $(CONFSRC)/to
 environment.o: $(CONFSRC)/environment.h
 tools.o: $(CONFSRC)/tools.h
 
+# Make sure qstring_compat.obj isn't compiled with PCH enabled
+qstring_compat.o: $(CORESRC)/tools/qstring_compat.cpp
+	$(CXX) -c $(CXXFLAGS_BARE) -o $@ $<
+
 clean:
 	-rm -f *.o
 	-rm -rf *.gch

tools/configure/Makefile.win32

@@ -163,3 +163,7 @@ quuid.obj: $(CORESRC)\plugin\quuid.cpp $(PCH)
 	$(CXX) -c $(CXXFLAGS) $<
 {$(CORESRC)\xml}.cpp{}.obj::
 	$(CXX) -c $(CXXFLAGS) $<
+
+# Make sure qstring_compat.obj isn't compiled with PCH enabled
+qstring_compat.obj: $(CORESRC)\tools\qstring_compat.cpp
+	$(CXX) -c $(CXXFLAGS_BARE) $(CORESRC)\tools\qstring_compat.cpp