Manual changes:
cpp.py: cope with macros that refer to other macros.
defaults.py: x86 no longer always implies __i386__; use __i386__ to replace
the kernel CONFIG_X86_32 flag.
asm/page.h: the upstream page.h isn't a uapi header and no longer includes
the stuff we were using it for. Let's just have our own static file, since
it's the same for all our architectures (both 32- and 64-bit).
sys/select.h: we used to use the various FD_SET-related macros from the
kernel header files, but they've gone. Adjust by adding trivial equivalent
definitions.
Automated changes:
libc/kernel/arch-x86, libc/kernel/common: regenerated from
external/kernel-headers.
Change-Id: I84fc0ed52dc742e043b4ae300fd3b58ee99b7fcd