doc: work around Texinfo 6.7 bug

[Akim Demaille]

commit af000bab111768a04021bf5ffa4bbe91d44e231c
Author: Akim Demaille <address@hidden>
Date:   Sat Nov 9 09:01:14 2019 +0100

    doc: work around Texinfo 6.7 bug
    
    When @code is used in a @deftype... definition, it issues quotes.
    Remove them.
    See https://lists.gnu.org/archive/html/help-texinfo/2019-11/msg00004.html.
    
    * doc/local.mk: here.

diff --git a/doc/local.mk b/doc/local.mk
index c0763767..cfd41ac6 100644
--- a/doc/local.mk
+++ b/doc/local.mk
@@ -54,6 +54,23 @@ $(CROSS_OPTIONS_TEXI): doc/bison.help $(CROSS_OPTIONS_PL)
        $(AM_V_at)mv $@.tmp $@
 MAINTAINERCLEANFILES = $(CROSS_OPTIONS_TEXI)
 
+
+# Fix Info's @code in @deftype
+# https://lists.gnu.org/archive/html/help-texinfo/2019-11/msg00004.html
+all: $(srcdir)/$(doc_bison).info.bak
+$(srcdir)/$(doc_bison).info.bak: $(srcdir)/$(doc_bison).info
+       $(AM_V_GEN) $(PERL) -pi.bak -0777       \
+         -e 's{(^ --.*\n(?: {10}.*\n)*)}'      \
+         -e '{'                                \
+         -e '  $$def = $$1;'                   \
+         -e '  $$def =~ s/‘|’//g;'             \
+         -e '  $$def;'                         \
+         -e '}gem;' $(srcdir)/$(doc_bison).info
+       @ touch $@
+EXTRA_DIST += $(srcdir)/$(doc_bison).info.bak
+MAINTAINERCLEANFILES += $(srcdir)/$(doc_bison).info.bak
+
+
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