https://bugs.gentoo.org/695918

The patchs fixes build failure against texinfo-6.7+:
```
Malformed UTF-8 character: \xcb\xeb (unexpected non-continuation byte 0xeb, immediately after start byte 0xcb;
need 2 bytes, got 1) in pattern match (m//) at /usr/share/texinfo/Texinfo/ParserNonXS.pm line 3364.
Malformed UTF-8 character (fatal) at /usr/share/texinfo/Texinfo/ParserNonXS.pm line 3364.
make[2]: *** [Makefile:472: a2ps.info] Error 25
```

Fixed-by: Neil Bothwick
--- a/doc/a2ps.texi~	2019-11-24 18:51:07.000000000 +0000
+++ a/doc/a2ps.texi	2019-11-24 18:56:30.390438433 +0000
@@ -1,5 +1,6 @@
 \input texinfo @c -*- texinfo -*-
 @c %**start of header
+@documentencoding ISO-8859-1
 @setfilename a2ps.info
 @settitle General Purpose PostScript Generating Utility
 @c @setchapternewpage odd

--- a/doc/regex.texi~	2002-03-04 18:46:24.000000000 +0000
+++ a/doc/regex.texi	2019-11-24 18:56:42.861052598 +0000
@@ -1,5 +1,6 @@
 \input texinfo
 @c %**start of header
+@documentencoding ISO-8859-1
 @setfilename regex.info
 @settitle Regex
 @c %**end of header

--- a/ogonkify/doc/ogonkify.texi~	2007-12-29 02:09:38.000000000 +0000
+++ a/ogonkify/doc/ogonkify.texi	2019-11-24 18:57:03.173424149 +0000
@@ -1,5 +1,6 @@
 \input texinfo   @c -*-texinfo-*-
 @c %**start of header
+@documentencoding ISO-8859-1
 @setfilename ogonkify.info
 @settitle Ogonkify
 @setchapternewpage off