From 9eea24ed601d0aa243269fac64c9a65c3750d1b0 Mon Sep 17 00:00:00 2001
From: Alexandru Croitor <alexandru.croitor@qt.io>
Date: Tue, 3 Dec 2019 16:07:44 +0100
Subject: [PATCH] Don't export private include paths if there are no private
 includes

Needed when building Qt Creator with CMake + Qt6 non-prefix build.
Specifically qttools's QtUiPlugin does not have any private headers,
but the non-existing include path was exported, which caused an error
when configuring Qt Creator.

Change-Id: I662bc502fe3134fba083bde273b7f63fe1470277
Reviewed-by: Leander Beernaert <leander.beernaert@qt.io>
Reviewed-by: Qt CMake Build Bot
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>
---
 cmake/QtBuild.cmake | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/cmake/QtBuild.cmake b/cmake/QtBuild.cmake
index a1b044b97d4..6f325adfb48 100644
--- a/cmake/QtBuild.cmake
+++ b/cmake/QtBuild.cmake
@@ -1462,9 +1462,12 @@ function(qt_add_module target)
     # Handle cases like QmlDevTools which do not have their own headers, but rather borrow them
     # from another module.
     if(NOT arg_NO_SYNC_QT AND NOT arg_NO_MODULE_HEADERS)
-        list(APPEND private_includes
-                    "$<BUILD_INTERFACE:${module_include_dir}/${PROJECT_VERSION}>"
-                    "$<BUILD_INTERFACE:${module_include_dir}/${PROJECT_VERSION}/${module}>")
+        # Don't include private headers unless they exist, aka syncqt created them.
+        if(module_headers_private)
+            list(APPEND private_includes
+                        "$<BUILD_INTERFACE:${module_include_dir}/${PROJECT_VERSION}>"
+                        "$<BUILD_INTERFACE:${module_include_dir}/${PROJECT_VERSION}/${module}>")
+        endif()
 
         list(APPEND public_includes
                     # For the syncqt headers