Follow Qt's OpenGL compile flags

Only link against OpenGL if Qt links against OpenGL. This ensures
that we don't run into issues if Qt links GLES and plasma links
GL because that's found.

REVIEW: 115990

CMakeLists.txt

@@ -115,7 +115,7 @@ set_package_properties(OpenGL PROPERTIES DESCRIPTION "The OpenGL libraries"
                        URL "http://www.opengl.org"
                        TYPE OPTIONAL
                       )
-if(OPENGL_FOUND)
+if(OPENGL_FOUND AND (${Qt5Gui_OPENGL_IMPLEMENTATION} STREQUAL "GL"))
     set(HAVE_GLX ${HAVE_X11})
 else()
     set(HAVE_GLX 0)

src/declarativeimports/core/CMakeLists.txt

@@ -61,7 +61,7 @@ if(HAVE_X11)
     target_link_libraries(corebindingsplugin ${XCB_SHAPE_LIBRARY})
   endif()
 
-  if(OPENGL_FOUND)
+  if(HAVE_GLX)
     target_link_libraries(corebindingsplugin ${OPENGL_gl_LIBRARY})
   endif()
 endif()