Fix doc snarfing with GCC 4.5+.
From <http://git.savannah.gnu.org/cgit/guile.git/commit/?h=branch_release-1-8&id=aac41d28358cea594bb30f6e547afb82bb6004a6>.

diff --git a/scripts/snarf-check-and-output-texi b/scripts/snarf-check-and-output-texi
index ea33e17..8cd42e8 100755
--- a/scripts/snarf-check-and-output-texi
+++ b/scripts/snarf-check-and-output-texi
@@ -267,6 +267,17 @@ exec ${GUILE-guile} -l $0 -c "(apply $main (cdr (command-line)))" "$@"
       (set! *file* file)
       (set! *line* line))
 
+     ;; newer gccs like to throw around more location markers into the
+     ;; preprocessed source; these (hash . hash) bits are what they translate to
+     ;; in snarfy terms.
+     (('location ('string . file) ('int . line) ('hash . 'hash))
+      (set! *file* file)
+      (set! *line* line))
+
+     (('location ('hash . 'hash) ('string . file) ('int . line) ('hash . 'hash))
+      (set! *file* file)
+      (set! *line* line))
+
      (('arglist rest ...)
       (set! *args* (do-arglist rest)))
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<div class='path'>path: <a href='/guix/log/?id=7779ed9aedb3f417280fedbfe7b85504d7fcfc3b'>root</a>/<a href='/guix/log/doc?id=7779ed9aedb3f417280fedbfe7b85504d7fcfc3b'>doc</a>/<a href='/guix/log/doc/fdl-1.3.texi?id=7779ed9aedb3f417280fedbfe7b85504d7fcfc3b'>fdl-1.3.texi</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/doc/fdl-1.3.texi?id=7779ed9aedb3f417280fedbfe7b85504d7fcfc3b&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2020-03-10 20:26:52 +0100'>2020-03-10</span></td><td><a href='/guix/commit/doc/fdl-1.3.texi?id=21656ffa3b6d78a610f0befced20cc9b4b3baab6'>doc: Use HTTPS for external links.</a><span class='msg-avail'>...<span class='msg-tooltip'>* doc/contributing.texi
  (14.1 Building from Git,
   14.3 The Perfect Setup,
   14.4.1 Software Freedom,
   14.4.4 Synopses and Descriptions,
   14.5.4 Formatting Code):
   Use HTTPS for @uref{}s and @url{}s that support it.

* doc/fdl-1.3.texi
  (Appendix A GNU Free Documentation License):
  Use HTTPS for @uref{}s and @url{}s that support it.

* doc/guix.texi
  (6.3 Build Systems,
   8.8.4 Networking Services,
   8.8.8 Sound Services,
   8.8.16 Web Services,
   8.11 Name Service Switch,
   12.2 Preparing to Use the Bootstrap Binaries);
   Use HTTPS for @uref{}s and @url{}s that support it.

Signed-off-by: Marius Bakke &lt;mbakke@fastmail.com&gt;
</span></span></td><td>Vitaliy Shatrov</td></tr>