-- Checking for module 'gstreamer-mpegts-1.0>=1.4.0'
--   No package 'gstreamer-mpegts-1.0' found
-- Checking for module 'gstreamer-pbutils-1.0 >= 1.18.4'
--   Found gstreamer-pbutils-1.0, version 1.28.6
-- Checking for module 'gstreamer-tag-1.0 >= 1.18.4'
--   Found gstreamer-tag-1.0, version 1.28.6
-- Checking for module 'gstreamer-video-1.0 >= 1.18.4'
--   Found gstreamer-video-1.0, version 1.28.6
-- Checking for module 'gstreamer-codecparsers-1.0 >= 1.18.4'
--   No package 'gstreamer-codecparsers-1.0' found
-- Checking for module 'gstreamer-transcoder-1.0 >= 1.18.4'
--   No package 'gstreamer-transcoder-1.0' found
-- Checking for module 'gstreamer-rtp-1.0 >= 1.18.4'
--   Found gstreamer-rtp-1.0, version 1.28.6
-- Checking for module 'gstreamer-sdp-1.0 >= 1.18.4'
--   Found gstreamer-sdp-1.0, version 1.28.6
-- Checking for module 'gstreamer-webrtc-1.0 >= 1.18.4'
--   No package 'gstreamer-webrtc-1.0' found
CMake Error at /usr/share/cmake-4.4/Modules/FindPackageHandleStandardArgs.cmake:290 (message):
  Could NOT find GStreamer (missing: GSTREAMER_MPEGTS_LIBRARIES) (found
  suitable version "1.28.6", minimum required is "1.18.4")
Call Stack (most recent call first):
  /usr/share/cmake-4.4/Modules/FindPackageHandleStandardArgs.cmake:654 (_FPHSA_FAILURE_MESSAGE)
  Source/cmake/FindGStreamer.cmake:142 (FIND_PACKAGE_HANDLE_STANDARD_ARGS)
  Source/cmake/GStreamerChecks.cmake:23 (find_package)
  Source/cmake/OptionsGTK.cmake:507 (include)
  Source/cmake/WebKitCommon.cmake:331 (include)
  CMakeLists.txt:22 (include)

If mpegts is not going to work on the build server, then remove its usage from webkitgtk

--- webkitgtk-2.53.92/Source/cmake/GStreamerDependencies.cmake.old
+++ webkitgtk-2.53.92/Source/cmake/GStreamerDependencies.cmake
@@ -3,7 +3,6 @@
 WEBKIT_OPTION_DEPEND(ENABLE_WEB_AUDIO USE_GSTREAMER)
 WEBKIT_OPTION_DEPEND(ENABLE_WEB_CODECS USE_GSTREAMER)
 WEBKIT_OPTION_DEPEND(USE_GSTREAMER_GL ENABLE_VIDEO)
-WEBKIT_OPTION_DEPEND(USE_GSTREAMER_MPEGTS ENABLE_VIDEO)
 WEBKIT_OPTION_DEPEND(USE_GSTREAMER_WEBRTC ENABLE_WEB_RTC)
 WEBKIT_OPTION_DEPEND(USE_FLITE ENABLE_SPEECH_SYNTHESIS)
 WEBKIT_OPTION_DEPEND(USE_SPIEL ENABLE_SPEECH_SYNTHESIS)
--- webkitgtk-2.53.92/Source/cmake/GStreamerChecks.cmake.old
+++ webkitgtk-2.53.92/Source/cmake/GStreamerChecks.cmake
@@ -9,7 +9,7 @@
       else ()
           set(GSTREAMER_COMPONENTS app pbutils)
           if (ENABLE_VIDEO)
-              list(APPEND GSTREAMER_COMPONENTS video mpegts tag gl)
+              list(APPEND GSTREAMER_COMPONENTS video tag gl)
           endif ()
 
           if (ENABLE_WEB_AUDIO)