oops

git-svn-id: http://haxe.googlecode.com/svn/trunk@5798 f16182fa-f095-11de-8f43-4547254af6c6
init context before executing build macros (fixed issue #1357)

git-svn-id: http://haxe.googlecode.com/svn/trunk@5799 f16182fa-f095-11de-8f43-4547254af6c6