[collectd] compile problems on NetBSD

[matthew sporleder]

I needed the following patch to get any plugins to work on NetBSD:

--- src/bind.c.orig     2009-07-26 21:51:32.000000000 -0400
+++ src/bind.c
@@ -21,7 +21,9 @@
  *   Florian Forster <octo at verplant.org>
  **/

+#ifdef __linux
 #define _XOPEN_SOURCE 600 /* glibc2 needs this for strptime */
+#endif

 #include "collectd.h"
 #include "common.h"

Otherwise there are a ton of errors about strtoll.  I don't know if
there's a better way for autoconf to test for this glibc requirement,
but it breaks NetBSD.  :)

Matt