fix non-git non-shadow non-prefix non-qtbase builds

these builds usually assume all headers in the qtbase build (== source
== install) dir, so the path for adding our pre-generated per-module
include paths needs to be triggered explicitly.

Change-Id: I57ec441d58cdf8186907ee6c36dce08daa206c49
Reviewed-by: Kai Koehne <kai.koehne@digia.com>
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>

mkspecs/features/qt_module_pris.prf

@@ -56,7 +56,8 @@ else: \
         MODULE_PRIVATE_INCLUDES = \$\$QT_MODULE_INCLUDE_BASE/$$MODULE_INCNAME/$$VERSION \
                                   \$\$QT_MODULE_INCLUDE_BASE/$$MODULE_INCNAME/$$VERSION/$$MODULE_INCNAME
     }
-    !git_build:!equals(_PRO_FILE_PWD_, $$OUT_PWD) {
+    !git_build:if(!equals(_PRO_FILE_PWD_, $$OUT_PWD) \
+                  |if(!prefix_build:!equals(MODULE_BASE_DIR, $$[QT_HOST_PREFIX]))) {
         pub_inc = $$replace(MODULE_INCLUDES, ^\\\$\\\$QT_MODULE_INCLUDE_BASE, $$MODULE_BASE_DIR/include)
         priv_inc = $$replace(MODULE_PRIVATE_INCLUDES, ^\\\$\\\$QT_MODULE_INCLUDE_BASE, $$MODULE_BASE_DIR/include)
         force_independent {