[PATCH v1 2/4] configure: Add check for lex, yacc

[Geoff Levand]

Signed-off-by: Geoff Levand <geoff at infradead.org>
---
 configure.ac | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/configure.ac b/configure.ac
index 3ed41ee..f394de6 100644
--- a/configure.ac
+++ b/configure.ac
@@ -26,7 +26,13 @@ AS_IF([test "x$CFLAGS" = "x"], [AC_SUBST([CFLAGS], [""])])
 
 AC_PROG_CC
 AC_PROG_LEX
+if test -z "$($LEX --version)"; then
+	AC_MSG_ERROR([[Please install flex/lex]])
+fi
 AC_PROG_YACC
+if test -z "$($YACC --version)"; then
+	AC_MSG_ERROR([[Please install bison/yacc]])
+fi
 AC_PROG_INSTALL
 
 AM_INIT_AUTOMAKE
-- 
2.11.0