From e28c6eb3b64a21e0239d556de9dce1620cb9a3bd Mon Sep 17 00:00:00 2001
From: Alexander Smorkalov <alexander.smorkalov@xperience.ai>
Date: Wed, 3 Jul 2024 19:22:06 +0300
Subject: [PATCH] Fixed gtkglext search in cmake.

---
 modules/highgui/cmake/detect_gtk.cmake | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/modules/highgui/cmake/detect_gtk.cmake b/modules/highgui/cmake/detect_gtk.cmake
index 5e9412d427..b7f53d1a9b 100644
--- a/modules/highgui/cmake/detect_gtk.cmake
+++ b/modules/highgui/cmake/detect_gtk.cmake
@@ -29,7 +29,15 @@ if(WITH_GTK)
   if((WITH_OPENGL OR HAVE_OPENGL) AND HAVE_GTK2)
     ocv_check_modules(GTKGLEXT gtkglext-1.0)
     if(HAVE_GTKGLEXT)
-      ocv_add_external_target(gtkglext "${GTKGLEXT_INCLUDE_DIRS}" "${GTKGLEXT_LIBRARIES}" "HAVE_GTKGLEXT")
+      # HACK for https://github.com/opencv/opencv/issues/20850
+      # pkg-config reports some include directories that do not exist. Just filter them out.
+      set(GTKGLEXT_INCLUDE_DIRS_EXISTS "")
+      foreach(p ${GTKGLEXT_INCLUDE_DIRS})
+        if (EXISTS "${p}")
+          list(APPEND GTKGLEXT_INCLUDE_DIRS_EXISTS "${p}")
+        endif()
+      endforeach()
+      ocv_add_external_target(gtkglext "${GTKGLEXT_INCLUDE_DIRS_EXISTS}" "${GTKGLEXT_LIBRARIES}" "HAVE_GTKGLEXT")
     endif()
   endif()
 elseif(HAVE_GTK)