make @iftex case work in texinfo-5.1

(cherry picked from commit 1846c7a35d1091d3b6140c56befd7fee0a91dcbb)

Signed-off-by: Ken Dreyer <ktdreyer@ktdreyer.com>
@end should only appear at a line beginning

Signed-off-by: Love Hornquist Astrand <lha@h5l.org>
(cherry picked from commit 0e0351776a48a69ec704085e554a0653d8179452)

Signed-off-by: Ken Dreyer <ktdreyer@ktdreyer.com>
fix for texinfo 5.1

Signed-off-by: Ken Dreyer <ktdreyer@ktdreyer.com>
(cherry picked from commit a1d7f1f3e3cc6717f32a517053015585c47177ba)
more texinfo 5.1 hacks

For hx509.texi, we need the copyright macros for both html and info.
Just remove the "ifhtml" conditionals.

For whatis.texi, texinfo 5.1 inserts the sub{} macro inline with no
newlines, so there are errors about @html not being at the end of a
line, etc.

(cherry picked from commit 115f88a3e7901541a67964d41bbd2a1866cfc521)
Merge pull request #36 from ktdreyer/heimdal-1-5-branch-texinfo51

texinfo 5.1 fixes for heimdal-1-5-branch