HelenOS sources

root/boot/generic/include/

[..]
align.h assert.h balloc.h byteorder.h errno.h
gzip.h halt.h inflate.h kernel.h macros.h
payload.h printf.h printf_core.h printf_verify.h putchar.h
tar.h uchar.h version.h
[..]
HelenOS homepage, sources at GitHub