automatically launch new configure system in top-level builds

this includes moving the -skip option here, where it belongs.
the implementation is a bit hacky, but the proper one would be vastly
more complex: we'd have to load all modules, then parse the command
line properly (the -skip parsing would be a custom callback, to avoid
needing to process features), then discard all now excluded modules
again, then re-process the command line (so we can complain about
options which are now invalid), and only now proceed with the actual
feature processing.
that seems a bit over the top, so we accept that -skip cannot be the
argument of another option, which seems quite reasonable.

Change-Id: I0053658e6d7e11b82cdfe55893cb553b664a9298
Reviewed-by: Jake Petroules <jake.petroules@qt.io>
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@qt.io>

configure.json

@@ -0,0 +1,7 @@
+{
+    "commandline": {
+        "options": {
+            "skip": "addString"
+        }
+    }
+}

qt.pro

@@ -1,12 +1,10 @@
 # Create the super cache so modules will add themselves to it.
 cache(, super)
 
-CONFIG += build_pass   # hack to disable the .qmake.super auto-add
-load(qt_build_config)
-CONFIG -= build_pass   # unhack, as it confuses Qt Creator
-
 TEMPLATE      = subdirs
 
+CONFIG += prepare_docs qt_docs_targets
+
 # Extract submodules from .gitmodules.
 lines = $$cat(.gitmodules, lines)
 for (line, lines) {
@@ -26,6 +24,29 @@ for (line, lines) {
 }
 QMAKE_INTERNAL_INCLUDED_FILES += $$PWD/.gitmodules
 
+QT_SKIP_MODULES =
+uikit {
+    QT_SKIP_MODULES += qtdoc qtmacextras qtserialport qtwebkit qtwebkit-examples
+    !ios: QT_SKIP_MODULES += qtscript
+}
+
+# This is a bit hacky, but a proper implementation is not worth it.
+args = $$QMAKE_EXTRA_ARGS
+for (ever) {
+    isEmpty(args): break()
+    a = $$take_first(args)
+
+    equals(a, -skip) {
+        isEmpty(args): break()
+        m = $$take_first(args)
+        contains(m, -.*): next()
+        m ~= s/^(qt)?/qt/
+        !contains(modules, $$m): \
+            error("-skip command line argument used with non-existent module '$$m'.")
+        QT_SKIP_MODULES += $$m
+    }
+}
+
 modules = $$sort_depends(modules, module., .depends .recommends)
 modules = $$reverse(modules)
 for (mod, modules) {
@@ -72,3 +93,5 @@ for (mod, modules) {
 
     SUBDIRS += $$mod
 }
+
+load(qt_configure)