makefile: correct dependencies to always generate build.h and compflag.h

Signed-off-by: Steven Noonan <steven@uplinklabs.net>

Created by  Steven Noonan  on October 18, 2009
X6SOE6NGIVFZU5FUOMJ6PV5PG47TUKTEMEHXOVWOOT43IH2PABNAC
Change contents