Made the C++ front-end more Creator-friendly.

src/libs/cplusplus/cplusplus-lib.pri

-DEFINES += HAVE_QT CPLUSPLUS_WITH_NAMESPACE CPLUSPLUS_BUILD_LIB
+DEFINES += CPLUSPLUS_BUILD_LIB
 INCLUDEPATH += $$PWD
 
 include(../../shared/cplusplus/cplusplus.pri)

src/libs/cplusplus/cplusplus.pri

 INCLUDEPATH += $$PWD/../../shared/cplusplus
-DEFINES += HAVE_QT CPLUSPLUS_WITH_NAMESPACE
 LIBS *= -l$$qtLibraryTarget(CPlusPlus)

src/shared/cplusplus/CPlusPlusForwardDeclarations.h

@@ -49,7 +49,7 @@
 #ifndef CPLUSPLUS_CPLUSPLUSFORWARDDECLARATIONS_H
 #define CPLUSPLUS_CPLUSPLUSFORWARDDECLARATIONS_H
 
-#ifdef HAVE_QT
+#ifndef CPLUSPLUS_WITH_NO_QT
 #  include <QtCore/qglobal.h>
 #  define CPLUSPLUS_BEGIN_HEADER
 #  define CPLUSPLUS_END_HEADER
@@ -58,6 +58,7 @@
 #  else
 #    define CPLUSPLUS_EXPORT Q_DECL_IMPORT
 #  endif
+#  define CPLUSPLUS_WITH_NAMESPACE
 #else
 #  define CPLUSPLUS_BEGIN_HEADER
 #  define CPLUSPLUS_END_HEADER