diff --git a/configure.in b/configure.in
index c1bd707..0f03233 100644
--- a/configure.in
+++ b/configure.in
@@ -537,7 +537,7 @@ esac
 
 SAVE_CFLAGS="$CFLAGS"
 SAVE_LIBS="$LIBS"
-LDAP_CFLAGS="-DLDAP_DEPRECATED"
+LDAP_CFLAGS="-DLDAP_DEPRECATED -I$with_openldap/include"
 CFLAGS="$CFLAGS $LDAP_CFLAGS"
 LIBS="$LIBS $LDAP_LIBS"
 AC_CHECK_FUNCS(ldap_ntlm_bind)