diff --git a/ol-unix.c b/ol-unix.c
index 6c4da65e..40307f38 100644
--- a/ol-unix.c
+++ b/ol-unix.c
@@ -13,6 +13,16 @@
 #include <netinet/in.h>
 #include <arpa/inet.h>
 
+#if !defined(HAVE_STRNLEN) /* Implement for platforms that lack strnlen */
+size_t strnlen (register const char* s, size_t maxlen) {
+  register const char *e;
+  size_t n;
+
+  for (e = s, n = 0; *e && n < maxlen; e++, n++);
+  return n;
+}
+#endif
+
 
 void ol_tcp_io(EV_P_ ev_io* watcher, int revents);
 void ol_tcp_connect(ol_handle* handle, ol_req* req);
diff --git a/ol.h b/ol.h
index bc593cbd..bbc9eaf6 100644
--- a/ol.h
+++ b/ol.h
@@ -18,13 +18,18 @@ typedef void (*ol_connect_cb)(ol_req* req, ol_err e);
 typedef void (*ol_shutdown_cb)(ol_req* req);
 
 
-#if defined(__unix__) || defined(__POSIX__)
+#if defined(__unix__) || defined(__POSIX__) || defined(__APPLE__)
 # include "ol-unix.h"
 #else
 # include "ol-win.h"
 #endif
 
 
+#if !defined(__APPLE__) /* FIXME: detect during configure */
+# define HAVE_STRNLEN
+#endif
+
+
 typedef enum {
   OL_UNKNOWN_HANDLE = 0,
   OL_TCP,