From: Fabian Vogt <fabian@ritter-vogt.de>
Subject: Forcee inclusion of _PRIVATE_INCLUDE_DIRS to CMakeConfig files
References: QTBUG-37417

This is broken for shadow builds otherwise.

Index: qtbase-opensource-src-5.9.1/mkspecs/features/create_cmake.prf
===================================================================
--- qtbase-opensource-src-5.9.1.orig/mkspecs/features/create_cmake.prf
+++ qtbase-opensource-src-5.9.1/mkspecs/features/create_cmake.prf
@@ -30,7 +30,6 @@ CMAKE_MODULE_NAME = $$cmakeModuleName($$
 
 split_incpath {
     CMAKE_ADD_SOURCE_INCLUDE_DIRS = true
-    CMAKE_NO_PRIVATE_INCLUDES = true # Don't add private includes in the build dir which don't exist
     CMAKE_SOURCE_INCLUDES = \
         $$cmakeTargetPaths($$QT_MODULE_INCLUDE_BASE $$QT_MODULE_INCLUDE_BASE/Qt$${CMAKE_MODULE_NAME})
     CMAKE_SOURCE_PRIVATE_INCLUDES = \
@@ -53,8 +52,6 @@ contains(CMAKE_INCLUDE_DIR, "^\\.\\./.*"
     CMAKE_INCLUDE_DIR_IS_ABSOLUTE = True
 }
 
-!exists($$first(QT.$${MODULE}_private.includes)): CMAKE_NO_PRIVATE_INCLUDES = true
-
 CMAKE_LIB_DIR = $$cmakeRelativePath($$[QT_INSTALL_LIBS], $$[QT_INSTALL_PREFIX])
 contains(CMAKE_LIB_DIR,"^\\.\\./.*") {
     CMAKE_LIB_DIR = $$[QT_INSTALL_LIBS]/