diff --git src/assuan-socket.c src/assuan-socket.c
index bffe480..57ee5b0 100644
--- src/assuan-socket.c
+++ src/assuan-socket.c
@@ -33,6 +33,9 @@
 # include <io.h>
 #endif
 #else
+#  if (__APPLE__ && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 1050)
+#   include <sys/select.h>
+#  endif
 # include <sys/types.h>
 # include <sys/socket.h>
 # include <netinet/in.h>
