What is syscalls.c for?

[Rob Landley]

Ok, I just looked at syscalls.c and module_syscalls.c.  There was a comment 
that "very old libc versions don't include these calls".  We no longer 
support libc5, correct?  Is compiling on alpha under 2.1 kernel still 
something we care deeply about in a busybox-1.0 and up world?

Just for kicks, I moved both of those files out of the directory and snipped 
them out of libbb/Makefile.in, then did a make allyesconfig, make clean, 
make.  It built without complaint, and seems to work just fine.

So my question is: under exactly what circumstances (if any) are these files 
still needed?  If any of it it _is_ still relevant, we need better 
documentation, and to prioritize the "compiler.h" consolidation I was talking 
about earlier for support of broken build environments...

Rob