backslashes in macro arguments

[Ralf Wildenhues]

Hello bug-texinfo readers,

with makeinfo 4.13, the following texinfo code snippet from Autoconf:

  @macro dvar{varname, default}
  @r...@var{\varname\} = @samp{\defaul...@r{]}@c
  @end macro

  @defmac m4_split (@var{string}, @dvar{regexp, [\t ]+})
  ...
  @end defmac

is missing the backslash before the 't' in the info output, but not in
the PDF output.  The texinfo documentation about @macro only documents
the need to double backslashes in the macro definition, but is silent
about macro arguments.

Cheers, and thanks for maintaining texinfo!
Ralf