[Bug libgomp/65070] libgomp calls syscall instruction directly

["nyh at math dot technion.ac.il" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65070

--- Comment #6 from Nadav Har'El <nyh at math dot technion.ac.il> ---
Andrew, the syscall instruction may indeed be the only ABI of the Linux kernel.
But I didn't create this issue on the Linux kernel mailing list, rather on the 
libgomp library's issue tracker. Looking a the libgomp it already uses the
"glibc" API (and therefore ABI), and not just the system call instruction. It
uses malloc() and friends (and not the sbrk() system call), stdio, pthread_*(),
and varios str* functions; So I was wondering why not use syscall() glibc
function instead of duplicating its definition.

I could understand a response which would say something like "We want libgomp
to be usable without glibc, so we try to avoid using glibc functions and use
x86 instructions directly". But unless I'm missing something, libgomp isn't
actually usable without glibc.