Get rid of unneccessary ioctls.

[trasz]

Summary

Prevent flex(1) from generating calls to isatty(3) - and, in turn,
TIOCGETA ioctls - when parsing nsswitch.conf(5).

[imp]

The flex man page suggests there's a performance improvement if we use -CF or -Cf as well. -CFr or -Cfr may also be beneficial since it beneficial. The man page warns against increased size, but I doubt the differences that were important when flex was written (1995) are relevant today. If we're looking at performance tuning, we should look here.

Adding -CFr does increase the size, but not be enough to matter:

  9978      4    88   10070   0x2756   nslexer.o.no-CFr
26883      4    80   26967   0x6957   nslexer.o.-CFr

so ~16k increase in size. If you have a way to benchmark things, you might see if this is faster or not.

[markj]

lib/libc/net/nslexer.l

57

Keep these sorted?

[trasz]

Fix ordering.

[trasz]

In D17564#374936, @imp wrote:

The flex man page suggests there's a performance improvement if we use -CF or -Cf as well. -CFr or -Cfr may also be beneficial since it beneficial. The man page warns against increased size, but I doubt the differences that were important when flex was written (1995) are relevant today. If we're looking at performance tuning, we should look here.

Adding -CFr does increase the size, but not be enough to matter:

  9978      4    88   10070   0x2756   nslexer.o.no-CFr
26883      4    80   26967   0x6957   nslexer.o.-CFr

so ~16k increase in size. If you have a way to benchmark things, you might see if this is faster or not.

I'll keep that in mind, although for now I'm just shaving off useless syscalls :-)