--- libev/configure.ac	2007/12/14 21:07:13	1.1
+++ libev/configure.ac	2014/09/05 16:01:19	1.37
@@ -1,17 +1,26 @@
-AC_INIT(ev_epoll.c)
+AC_INIT
 
-AM_INIT_AUTOMAKE(libev,1.85)
-AM_CONFIG_HEADER(config.h)
+orig_CFLAGS="$CFLAGS"
+
+AC_CONFIG_SRCDIR([ev_epoll.c])
+
+AM_INIT_AUTOMAKE(libev,4.18) dnl also update ev.h!
+AC_CONFIG_HEADERS([config.h])
 AM_MAINTAINER_MODE
 
 AC_PROG_CC
-AC_PROG_INSTALL
-AC_PROG_LIBTOOL
 
-if test "x$GCC" = xyes ; then
-  CFLAGS="$CFLAGS -O3"
+dnl Supply default CFLAGS, if not specified
+if test -z "$orig_CFLAGS"; then
+  if test x$GCC = xyes; then
+    CFLAGS="-g -O3"
+  fi
 fi
 
+AC_PROG_INSTALL
+AC_PROG_LIBTOOL
+
 m4_include([libev.m4])
 
-AC_OUTPUT(Makefile)
+AC_CONFIG_FILES([Makefile])
+AC_OUTPUT