It's about time...
Take a look at bug 380063 that can't block this stabilization.
Imho it can't change the functionality of the program, so amd64 ok for me
Tested on x86, all good here ...
amd64 ok
+ 22 Aug 2011; Tony Vroon <chainsaw@gentoo.org> kbuild-0.1.5_p2-r1.ebuild: + Mark stable on AMD64 based on arch testing by Agostino "ago" Sarubbo & Ian + "idella4" Delaney in bug #380005 filed by Lars "Polynomial-C" Wendler.
Archtested on x86: Everything fine
x86 stable, thanks JD