added PREREQ macro to ensure suitable version of autoconf

diff --git a/configure.in b/configure.in
index 9b47fc6..5354fb5 100644 (file)
--- a/configure.in
+++ b/configure.in
@@ -1,4 +1,5 @@
 AC_INIT(libasyncio, 0.2)
+AC_PREREQ([2.50])
 AM_INIT_AUTOMAKE
 AM_CONFIG_HEADER(asyncio_config.hpp)