Restore 'tell-truth-about-private-API' patch

qt6-qtbase.spec

@@ -65,6 +65,7 @@ Source6: 10-qt6-check-opengl2.sh
 # macros
 Source10: macros.qt6-qtbase
 
+Patch1: qtbase-tell-the-truth-about-private-API.patch
 Patch2: qtbase-use-qgnomeplatform-as-default-platform-theme-on-gnome.patch
 
 # upstreamable patches

qtbase-tell-the-truth-about-private-API.patch

@@ -0,0 +1,28 @@
+From 25e78cce15fdf737cc48ed5d7683ad1d01b55621 Mon Sep 17 00:00:00 2001
+From: Christophe Giboudeaux <christophe@krop.fr>
+Date: Sun, 20 Sep 2020 09:57:22 +0200
+Subject: [PATCH] Tell the truth about private API
+
+Mark private API with symbols only for the current patch release
+
+This change is a port of the libqt5-qtbase patch which was
+added during the Qt 5.6 cycle.
+---
+ cmake/QtFlagHandlingHelpers.cmake | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/cmake/QtFlagHandlingHelpers.cmake b/cmake/QtFlagHandlingHelpers.cmake
+index d8597326cc..f9da7b2171 100644
+--- a/cmake/QtFlagHandlingHelpers.cmake
++++ b/cmake/QtFlagHandlingHelpers.cmake
+@@ -23,7 +23,7 @@ function(qt_internal_add_linker_version_script target)
+     endif()
+
+     if(TEST_ld_version_script)
+-        set(contents "Qt_${PROJECT_VERSION_MAJOR}_PRIVATE_API {\n    qt_private_api_tag*;\n")
++        set(contents "Qt_${PROJECT_VERSION_MAJOR}.${PROJECT_VERSION_MINOR}.${PROJECT_VERSION_PATCH}_PRIVATE_API {\n    qt_private_api_tag*;\n")
+         if(arg_PRIVATE_HEADERS)
+             foreach(ph ${arg_PRIVATE_HEADERS})
+                 string(APPEND contents "    @FILE:${ph}@\n")
+--
+2.40.0