Add check specifically for Bison and for Bison version >= 1.25.

svn path=/trunk/yasm/; revision=1061

diff --git a/configure.ac b/configure.ac
index 0132a2f817b8bbacb0e615d4ca47b75194f986de..3aca6ff3ea9a052c2611c9ffe26c3063136eb0ee 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -55,8 +55,18 @@ esac])
 #
 # Checks for programs.
 #
-# lex and yacc are only required for development.
 AC_PROG_YACC
+# check for Bison in particular
+if test "$YACC" != "bison -y"; then
+       AC_MSG_WARN([You will need bison if you want to regenerate parsers.])
+else
+       AC_MSG_CHECKING([bison version])
+       set `bison --version | sed -e 's/^@<:@A-Za-z() @:>@*//' -e 's/\./ /'`
+       if test "$1" = "1" -a "$2" -lt "25"; then
+               AC_MSG_WARN([You will need bison 1.25 or better if you want to regenerate parsers (found $1.$2).])
+       fi
+       AC_MSG_RESULT([$1.$2 (ok)])
+fi
 AC_PROG_CC_STDC
 AC_PROG_INSTALL
 AC_PROG_LN_S