The main thing here is to make the macros a bit safer by wrapping the macro argument evaluations in parens. Since that already touching huge portion of the file, I went a bit further and make the whitespace style uniform throughout the file. The other two small patches just unify the i-g-t and libdrm copies of the file a bit more. The diff between them is now just a few macros existing in only one copy, some whitespace/word difference in the license text, and different copyright holders :)
