Documentation build regressions

Hi,

 I haven't run `make pdf' for a while and consequently I have only now 
noticed that it does not work anymore as TeX chokes on input.  I have 
tracked down the two offending commits to be:

commit e698b8c41cbb2648a11a2ae806922c44d1482aed
Author: Doug Evans <[email protected]>
Date:   Tue Jun 3 00:29:49 2014 -0700

    Add command support for Guile.

for a failure in `guile.texi':

.../gdb/doc/guile.texi:1711: Unbalanced parentheses in @def.
@badparencount ...{Unbalanced parentheses in @def}
                                                  @global @parencount =0
@checkparencounts ...ount =0 @else @badparencount
                                                  @fi @ifnum @brackcount =0 ...

@printdefunline ...enalty 10002 @checkparencounts
                                                  @endgroup
l.1711 ...x? prefix@r{]} @r{[}#:doc doc-string{]})

?

and:

commit 824cc835aa9a4d585d955db4ab2a5dd4c17cc22c
Author: Phil Muldoon <[email protected]>
Date:   Thu Dec 7 16:47:33 2017 +0000

    Implement explicit locations for Python breakpoints.

for a failure in `python.texi':

.../gdb/doc/python.texi:4881: Unbalanced square braces in @def.
@badbrackcount ...nbalanced square braces in @def}
                                                  @global @brackcount =0
@checkparencounts ...ount =0 @else @badbrackcount
                                                  @fi
@printdefunline ...enalty 10002 @checkparencounts
                                                  @endgroup
l.4881 ...n @r{]}, label @r{]}, line @r{]]]]]]]]})

?

The latter file and offending line has been modified since and still fails 
in a similar manner.  If I revert both files to just before the respective 
commits, then `make pdf' succeeds.  This is with:

This is pdfeTeXk, Version 3.141592-1.21a-2.2 (Web2C 7.5.4)

You surely must have verified your changes before committing and the 
former one is especially old, so am I missing something?  I find it hard 
to believe nobody has tripped over it so far.

  Maciej