build: check for configure before trying to configure a subproject

diff --git a/m4/config_subdirs.m4 b/m4/config_subdirs.m4
index 95e58ee670c19dbd4b502eb7003431f03c838814..83d9594623446dec8d963c389172ab12f8ca48c7 100644 (file)
--- a/m4/config_subdirs.m4
+++ b/m4/config_subdirs.m4
@@ -8,7 +8,7 @@
 AC_DEFUN([lldp_CONFIG_SUBDIRS], [
   AC_CONFIG_SUBDIRS([$1])
   ac_dir="m4_normalize([$1])"
-  if test -d "$srcdir/$ac_dir"; then
+  if test -f "$srcdir/$ac_dir/configure"; then
     ac_sub_configure_args=
     ac_prev=
     eval "set x $ac_configure_args"