Commit Briefs
libthread: use consistent stack calculation code in makecontext
Also reduce duplication: makecontext is per-arch not per-os-arch. May fix #353.
libthread: remove Linux 2.4 code
Linux.c was for Linux 2.4 and is no longer used directly, only indirectly because NetBSD.c was a 1-line file #including Linux.c. So mv Linux.c NetBSD.c. Also rm Linux-*-asm.s which was for Linux 2.4 as well.
Trivial changes: whitespace and modes.
Remote whitespace at the ends of lines. Remove blank lines from the ends of files. Change modes on source files so that they are not executable. Signed-off-by: Dan Cross <cross@gajendra.net>