for syscalls, so one frame was lost in backtraces from syscalls.
This is handled better in the kernel by using a different mcount
entry point for profiling before the frame pointer is set up.
Expand RCSID().
Use .p2align instead of the ambiguous .align.
Added idempotency ifdef.
Removed unused macros ALTENTRY(), ALTASENTRY(), ASENTRY(), _MID_ENTRY.
Cleaned up formatting.
Reviewed by: jdp reviewed an old version
Obtained from: parts from NetBSD
