From 42761668c0300afa7f8bf5ba736458a818cd5d15 Mon Sep 17 00:00:00 2001
From: Akim Demaille <akim@lrde.epita.fr>
Date: Tue, 19 Mar 2013 11:19:17 -0700
Subject: AC_PROG_YACC: don't force Bison to warn against its own features
When invoked with -y/--yacc, Bison warns when its extensions over
POSIX Yacc are used. Yet many packages requiring GNU Bison use
Autoconf/Automake's Yacc support, which passes -y to Bison. It
turns out that passing '-o y.tab.c' has exactly the desired
effect: generating not only y.tab.c but also y.tab.h with -d and
y.output with -v. See:
http://lists.gnu.org/archive/html/bison-patches/2013-02/msg00100.html
* lib/autoconf/programs.m4 (AC_PROG_YACC): Use bison -o y.tab.c.
* NEWS, doc/autoconf.texi: Document this change.
---
NEWS | 4 ++++
doc/autoconf.texi | 2 +-
lib/autoconf/programs.m4 | 4 ++--
3 files changed, 7 insertions(+), 3 deletions(-)
diff --git a/doc/autoconf.texi b/doc/autoconf.texi
index c54c5b3..f895e47 100644
--- doc/autoconf.texi
+++ doc/autoconf.texi
@@ -4222,7 +4222,7 @@ and is cached in the @code{ac_cv_path_SED} variable.
@ovindex YACC
@caindex prog_YACC
If @code{bison} is found, set output variable @code{YACC} to @samp{bison
--y}. Otherwise, if @code{byacc} is found, set @code{YACC} to
+-o y.tab.c}. Otherwise, if @code{byacc} is found, set @code{YACC} to
@samp{byacc}. Otherwise set @code{YACC} to @samp{yacc}.
The result of this test can be influenced by setting the variable
@code{YACC} or the cache variable @code{ac_cv_prog_YACC}.
diff --git a/lib/autoconf/programs.m4 b/lib/autoconf/programs.m4
index f7af8b5..2057e78 100644
--- lib/autoconf/programs.m4
+++ lib/autoconf/programs.m4
@@ -892,10 +892,10 @@ AN_PROGRAM([yacc], [AC_PROG_YACC])
AN_PROGRAM([byacc], [AC_PROG_YACC])
AN_PROGRAM([bison], [AC_PROG_YACC])
AC_DEFUN([AC_PROG_YACC],
-[AC_CHECK_PROGS(YACC, 'bison -y' byacc, yacc)dnl
+[AC_CHECK_PROGS(YACC, 'bison -o y.tab.c' byacc, yacc)dnl
AC_ARG_VAR(YACC,
[The `Yet Another Compiler Compiler' implementation to use. Defaults to
-the first program found out of: `bison -y', `byacc', `yacc'.])dnl
+the first program found out of: `bison -o y.tab.c', `byacc', `yacc'.])dnl
AC_ARG_VAR(YFLAGS,
[The list of arguments that will be passed by default to $YACC. This script
will default YFLAGS to the empty string to avoid a default value of `-d' given
--
cgit v1.0-41-gc330