QmlJSDebugger: Check for Qt 4.7.1 or newer before enabling qml debugging

Reviewed-by: Christiaan Janssen

share/qtcreator/templates/qmlapp/qmlapplicationviewer/qmlapplicationviewer.pri

@@ -10,16 +10,45 @@ INCLUDEPATH += $$PWD
 contains(DEFINES, QMLOBSERVER) {
     DEFINES *= QMLJSDEBUGGER
 }
+
+defineTest(minQtVersion) {
+    maj = $$1
+    min = $$2
+    patch = $$3
+    isEqual(QT_MAJOR_VERSION, $$maj) {
+        isEqual(QT_MINOR_VERSION, $$min) {
+            isEqual(QT_PATCH_VERSION, $$patch) {
+                return(true)
+            }
+            greaterThan(QT_PATCH_VERSION, $$patch) {
+                return(true)
+            }
+        }
+        greaterThan(QT_MINOR_VERSION, $$min) {
+            return(true)
+        }
+    }
+    return(false)
+}
+
 contains(DEFINES, QMLJSDEBUGGER) {
     CONFIG(debug, debug|release) {
+        !minQtVersion(4, 7, 1) {
+            warning()
+            warning("Debugging QML requires the qmljsdebugger library that ships with Qt Creator.")
+            warning("This library requires Qt 4.7.1 or newer.")
+            warning()
+
+            error("Qt version $$QT_VERSION too old for QmlJS Debugging. Aborting.")
+        }
         isEmpty(QMLJSDEBUGGER_PATH) {
             warning()
-            warning(Debugging QML requires the qmljsdebugger library that ships with Qt Creator.)
-            warning(Please specify its location on the qmake command line, e.g.)
-            warning(  qmake -r QMLJSDEBUGGER_PATH=$CREATORDIR/share/qtcreator/qml/qmljsdebugger)
+            warning("Debugging QML requires the qmljsdebugger library that ships with Qt Creator.")
+            warning("Please specify its location on the qmake command line, eg")
+            warning("  qmake -r QMLJSDEBUGGER_PATH=$CREATORDIR/share/qtcreator/qmljsdebugger")
             warning()
 
-            error(QMLJSDEBUGGER defined, but no QMLJSDEBUGGER_PATH set on command line. Aborting.)
+            error("QMLJSDEBUGGER defined, but no QMLJSDEBUGGER_PATH set on command line. Aborting.")
             DEFINES -= QMLJSDEBUGGER
         } else {
             include($$QMLJSDEBUGGER_PATH/qmljsdebugger-lib.pri)