I'm getting next error: syscalls/access.S:1:24: asm/unistd.h: No such file or directory make[2]: *** [syscalls/access.o] Ошибка 1 make[1]: *** [syscalls/static.obj] Ошибка 2 make: *** [klibc] Ошибка 2 after some investigation i found that this occurs because klibc builded twice, one at src_compile with emake MISCFLAGS, and the second one at src_install with make DESDIR=${D} install. So because my kernel builded in KBUILD_OUTPUT_PREFIX asm/unistd.h can't be found at the second time. But the real problem is the fact that klibc builded in install again. Now i've just copy/paste miscflags section from src_compile to src_install and successfully emerge splashutils after that.
I'm sorry, but KBUILD_OUTPUT_PREFIX is deprecated. You should use KBUILD_OUTPUT instead. Support for KBUILD_OUTPUT has just been merged into the splashutils ebuilds, so you shouldn't experience any problems. If you do, feel free to reopen this bug/file another one.