G_(UN)?LIKELY() should be only used on whole conditional expressions,
and only if the branching is very highly predictable, not if it is only
more probable.

These macros should be used with care because a wrong prediction may
be a lot worst than what a good prediction can give.

git-svn-id: https://geany.svn.sourceforge.net/svnroot/geany/trunk@5625 ea778897-0a13-0410-b9d1-a72fbfd435f5