[LyX/master] Avoid \@ifundefined after user preamble

[Jürgen Spitzmüller]

Am Sonntag, dem 10.01.2021 um 11:58 -0500 schrieb Richard Kimberly
Heck:
> There are other uses of \@ifundefined in lib/layouts/. I'm happy to
> fix them, 

The special case here was that this is output after the user preamble.
Only in this case we have problems if users set \makeatletter.

I think with layouts things are not as urgent.

> but just to be clear: This construct accepts an \else clause?
> So
> \@ifundefined{#1}{#2} should become:
> 
> \ifdefined
> #2
> \else
> #1
> \fi
> 
> yes?

Yes, you can use \else if needed. See
http://www.texfaq.org/FAQ-isdef

Jürgen

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 488 bytes
Desc: This is a digitally signed message part
URL: <http://lists.lyx.org/pipermail/lyx-cvs/attachments/20210110/d88ad490/attachment.asc>