m4: use a safer pattern to enable/disable output

[bison.git] / configure.ac

diff --git a/configure.ac b/configure.ac
index 86783d525578f2dffd1400a9e8218bdd5896624f..83e20acb01ade45da8f32b2fd046315dd6bd1a16 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -132,6 +132,7 @@ AC_SUBST([YACC_SCRIPT])
 AC_SUBST([YACC_LIBRARY])
 
 # Checks for programs.
+AM_MISSING_PROG([DOT], [dot])
 AC_PROG_LEX
 $LEX_IS_FLEX || AC_MSG_ERROR([Flex is required])
 AC_PROG_YACC