window: add wrapper for EPOLL_CLOEXEC

Android does not have EPOLL_CLOEXEC, so add a fallback.

Signed-off-by: Pekka Paalanen <ppaalanen@gmail.com>
diff --git a/shared/os-compatibility.h b/shared/os-compatibility.h
index ca753b6..6ada7b6 100644
--- a/shared/os-compatibility.h
+++ b/shared/os-compatibility.h
@@ -36,4 +36,7 @@
 int
 os_socketpair_cloexec(int domain, int type, int protocol, int *sv);
 
+int
+os_epoll_create_cloexec(void);
+
 #endif /* OS_COMPATIBILITY_H */