From 44362487adc81cb786867d174f43684d56b030bb Mon Sep 17 00:00:00 2001
From: Ruben Kerkhof <ruben@rubenkerkhof.com>
Date: Sat, 27 Dec 2014 18:11:55 +0100
Subject: [PATCH] Check for bison instead of yacc

Bail out if we need it but can't find it.
Part of #774
---
 configure.ac           |  2 +-
 m4/pdns_check_bison.m4 | 15 +++++++++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)
 create mode 100644 m4/pdns_check_bison.m4

diff --git a/configure.ac b/configure.ac
index 19cda8696..1b36736a6 100644
--- a/configure.ac
+++ b/configure.ac
@@ -18,7 +18,7 @@ AC_CANONICAL_HOST
 
 AC_PROG_CC
 AM_PROG_CC_C_O
-AC_PROG_YACC
+PDNS_CHECK_BISON
 AM_PROG_LEX
 AC_PROG_INSTALL
 AC_PROG_MAKE_SET
diff --git a/m4/pdns_check_bison.m4 b/m4/pdns_check_bison.m4
new file mode 100644
index 000000000..7f1c83c13
--- /dev/null
+++ b/m4/pdns_check_bison.m4
@@ -0,0 +1,15 @@
+AC_DEFUN([PDNS_CHECK_BISON], [
+  AC_REQUIRE([AC_PROG_YACC])
+  AC_REQUIRE([AC_PROG_EGREP])
+
+  AC_CACHE_CHECK([if bison is the parser generator],[pdns_cv_prog_bison],[
+    AS_IF([$YACC --version 2>/dev/null | $EGREP -q '^bison '],
+      [pdns_cv_prog_bison=yes], [pdns_cv_prog_bison=no])
+  ])
+
+  AS_IF([test "x$pdns_cv_prog_bison" = "xno"], [
+    AS_IF([test ! -f "${srcdir}/pdns/bindparser.cc"],
+      [AC_MSG_ERROR([bison is missing and you don't have ${srcdir}/pdns/bindparser.cc. Please install bison])]
+    )]
+  )
+])
-- 
2.40.0