It allows to enable it easily in GLES renderer. And we check if this extension is available anyway because it's needed for shadows, so we can use it for other shaders too.
Only heightmap sim require version 140.
git-svn-id: svn+ssh://svn.code.sf.net/p/supertuxkart/code/main/trunk@14995 178a84e3-b1eb-0310-8ba1-8eac791a3b58