Merge topic 'FindOpenGL-no-X11'

d051cbda FindOpenGL: Drop explicit dependency on X11 (#15268)

Help/release/dev/FindOpenGL-no-X11.rst

+FindOpenGL-no-X11
+-----------------
+
+* The :module:`FindOpenGL` module no longer explicitly searches
+  for any dependency on X11 libraries with the :module:`FindX11`
+  module.  Such dependencies should not need to be explicit.
+  Applications using X11 APIs themselves should find and link
+  to X11 libraries explicitly.

Modules/FindOpenGL.cmake

@@ -138,19 +138,6 @@ else()
   unset(_OPENGL_INCLUDE_PATH)
   unset(_OPENGL_LIB_PATH)
 
-  # On Unix OpenGL most certainly always requires X11.
-  # Feel free to tighten up these conditions if you don't
-  # think this is always true.
-
-  if (OPENGL_gl_LIBRARY)
-    if(NOT X11_FOUND)
-      include(${CMAKE_CURRENT_LIST_DIR}/FindX11.cmake)
-    endif()
-    if (X11_FOUND)
-      set (OPENGL_LIBRARIES ${X11_LIBRARIES})
-    endif ()
-  endif ()
-
   find_library(OPENGL_glu_LIBRARY
     NAMES GLU MesaGLU
     PATHS ${OPENGL_gl_LIBRARY}