Proper provision of syscalls?

[Rick Mann]

I've got a more-or-less working newlib-1.15, binutils-2.17, gcc-4.2.2,  
combined tree build, built with --disable-newlib-supplied-syscalls.  
Our project is an FAA-certified thing, so we will be rolling all of  
our own support (bootloader, OS services, etc.); eventually we'll even  
have to go through newlib and strip out any unused source (yes, it  
truly sucks).

What's the "best practice" way of provisioning the syscalls? To build  
as I did, and provide the syscalls myself (what we currently do, and  
it works)? To build as I did, but link explicitly against libgloss,  
and provide duplicate symbols where I want to override libgloss? Use  
another library in there somewhere?

Is there a document somewhere that describes usage at this level?

I'd really appreciate the suggestions. Thanks!

-- 
Rick