divide select module into two modules: Unix and Win32 ones

auto/sources

diff --git a/auto/sources b/auto/sources
index 319026b..e4649b0 100644
--- a/auto/sources
+++ b/auto/sources
@@ -95,6 +95,7 @@
 
 SELECT_MODULE=ngx_select_module
 SELECT_SRCS=src/event/modules/ngx_select_module.c
+WIN32_SELECT_SRCS=src/event/modules/ngx_win32_select_module.c
 
 POLL_MODULE=ngx_poll_module
 POLL_SRCS=src/event/modules/ngx_poll_module.c