--- libev/configure.ac	2008/07/05 02:25:40	1.15
+++ libev/configure.ac	2016/12/28 04:22:06	1.42
@@ -1,17 +1,26 @@
 AC_INIT
+
+orig_CFLAGS="$CFLAGS"
+
 AC_CONFIG_SRCDIR([ev_epoll.c])
 
-AM_INIT_AUTOMAKE(libev,3.43)
+dnl also update ev.h!
+AM_INIT_AUTOMAKE(libev,4.24)
 AC_CONFIG_HEADERS([config.h])
 AM_MAINTAINER_MODE
 
-AC_PROG_INSTALL
-AC_PROG_LIBTOOL
+AC_PROG_CC
 
-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_CONFIG_FILES([Makefile])