support for these was recently added to sysmacros.h. note that the
syscall argument is a long, despite dev_t being 64-bit, so on 32-bit
archs the high bits will be lost. it appears the high bits are just
glibc silliness and not part of the kernel api, anyway, but it's nice
that we have them there for future expansion if needed.
to deal with the fact that the public headers may be used with pre-c99
compilers, __restrict is used in place of restrict, and defined
appropriately for any supported compiler. we also avoid the form
[restrict] since older versions of gcc rejected it due to a bug in the
original c99 standard, and instead use the form *restrict.
Rich Felker