bug#24069: [PATCHv3] Re: bug#24069: gcc man page is broken

[Maxim Cournoyer <maxim.cournoyer@gmail.com>]

Patch v3 still doesn't fix the problem. There are now pod2man errors
that prevent correctly generating the man pages:

--8<---------------cut here---------------start------------->8---
Makefile:3076: update target 'gcc.pod' due to: ../../gcc-5.4.0/gcc/doc/invoke.texi ../../gcc-5.4.0/gcc/doc/cppenv.texi ../../gcc-5.4.0/gcc/doc/cppopts.texi gcc-vers.texi
echo timestamp > gcc.pod
perl ../../gcc-5.4.0/gcc/../contrib/texi2pod.pl ../../gcc-5.4.0/gcc/doc/invoke.texi > gcc.pod
Unescaped left brace in regex is illegal here in regex; marked by <-- HERE in m/^\@strong{ <-- HERE (.*)}$/ at ../../gcc-5.4.0/gcc/../contrib/texi2pod.pl line 319.
make: [Makefile:3077: gcc.pod] Error 255 (ignored)
Makefile:3054: update target 'doc/gcc.1' due to: gcc.pod
echo timestamp > doc/gcc.1
(pod2man --center="GNU" --release="gcc-5.4.0" --date=2016-06-03 --section=1 gcc.pod > doc/gcc.1.T$$ && \
        mv -f doc/gcc.1.T$$ doc/gcc.1) || \
        (rm -f doc/gcc.1.T$$ && exit 1)
pod2man: unable to format gcc.pod
make: [Makefile:3055: doc/gcc.1] Error 1 (ignored)
Makefile:3085: update target 'gpl.pod' due to: ../../gcc-5.4.0/gcc/doc/include/gpl_v3.texi
echo timestamp > gpl.pod
perl ../../gcc-5.4.0/gcc/../contrib/texi2pod.pl ../../gcc-5.4.0/gcc/doc/include/gpl_v3.texi > gpl.pod
Unescaped left brace in regex is illegal here in regex; marked by <-- HERE in m/^\@strong{ <-- HERE (.*)}$/ at ../../gcc-5.4.0/gcc/../contrib/texi2pod.pl line 319.
make: [Makefile:3086: gpl.pod] Error 255 (ignored)
Makefile:3060: update target 'doc/gpl.7' due to: gpl.pod
echo timestamp > doc/gpl.7
(pod2man --center="GNU" --release="gcc-5.4.0" --date=2016-06-03 --section=7 gpl.pod > doc/gpl.7.T$$ && \
        mv -f doc/gpl.7.T$$ doc/gpl.7) || \
        (rm -f doc/gpl.7.T$$ && exit 1)
pod2man: unable to format gpl.pod
make: [Makefile:3061: doc/gpl.7] Error 1 (ignored)
../../gcc-5.4.0/gcc/cp/Make-lang.in:189: update target 'doc/g++.1' due to: doc/gcc.1
cp doc/gcc.1 doc/g++.1
rm gcc.pod
make: Leaving directory '/tmp/guix-build-gcc-5.4.0.drv-0/build/gcc'
--8<---------------cut here---------------end--------------->8---

I could trigger this output by cd'ing into the failed derivation and
running:

--8<---------------cut here---------------start------------->8---
cd /tmp/guix-build-gcc-5.4.0.drv-0
# running guix environment from stable guix pull, so need to add perl manually
guix environment --no-grafts gcc@5.4.0 --ad-hoc perl
make configure-gcc && make --trace -C gcc doc
--8<---------------cut here---------------end--------------->8---

Continuing investigation...