* Makerules (COMPILE.s): New variable.
* sysdeps/unix/Makefile (sysd-syscalls): New target; generate with
make-syscalls.sh and include it.
[$(subdir)=misc] (sysdep_routines): Append extra syscalls from
sysd-syscalls.
* sysdeps/unix/make-syscalls.sh: New file.
* Makerules (COMPILE.S): New variable.