cmake: use absolute library paths from 'pkgconfig'

- drop legacy check_module() macro
- drop 'ALIASOF_'

modules/highgui/CMakeLists.txt

@@ -128,8 +128,8 @@ elseif(HAVE_COCOA)
   list(APPEND HIGHGUI_LIBRARIES "-framework Cocoa")
 endif()
 
-if(UNIX)
-  #these variables are set by CHECK_MODULE macro
+if(TRUE)
+  # these variables are set by 'ocv_append_build_options(HIGHGUI ...)'
   foreach(P ${HIGHGUI_INCLUDE_DIRS})
     ocv_include_directories(${P})
   endforeach()