--- libev/configure.ac	2009/01/07 20:45:52	1.21
+++ libev/configure.ac	2018/12/21 06:58:50	1.43
@@ -1,17 +1,26 @@
-AC_INIT
+dnl also update ev.h!
+AC_INIT([libev], [4.25])
+
+orig_CFLAGS="$CFLAGS"
+
 AC_CONFIG_SRCDIR([ev_epoll.c])
+AM_INIT_AUTOMAKE
 
-AM_INIT_AUTOMAKE(libev,3.52)
 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])