wrong new indices accepted

[Patrice Dumas]

Hello,

makeinfo accepts the following defindex (only the first is licit according
to the manual):

@defindex aa
@defindex 11
@defindex
@defindex aaa
@defindex a
@defindex &

without warning... and even produce the right output when using the 
corresponding @*index and @printindex.

texi2dvi also accept those commands, and only choke on
@11index

The texi2dvi result, however is wrong for all but the correct index. 
texi2dvi also creates the fun file names corresponding with the fun index
names...

As usuall, I found that while testing what was the correct behavior to
implement in texi2html. So among the index names above which one is right
and which one is wrong? I believe makeinfo should warn for the wrong
ones.

I attach the whole test file.

--
Pat

bad_defined.texi
Description: TeXInfo document