Squashed 'OpenVPN Adapter/Vendors/openvpn/' changes from da99df6..4095565

4095565 OpenVPN 3 client: added tun abstraction layer.
4bfaafc AsioTimer: use expires_after() method when possible.
782e8eb Apple: moved some source files.
f89da96 OpenVPN 3 client: added single-thread mode:
233dfde OpenVPN 3 client: fixed state->session typos.
d689b6d Added new Apple Core Foundation wrappers:
3838a62 i/o layer: added OPENVPN_IO_REQUIRES_STOP compile flag.
138ec96 asiopolysock.hpp: don't call SockOpt::set_cloexec(fd) if fd is undefined (i.e. fd == -1).
10eb723 Apple CF wrapper: renamed OWN/BORROW.
962fe87 Apple CF wrapper: simplify cf.hpp dependency profile.
4fcc99c Objective C++: fix symbol conflicts.
8f63cbb tunwrapasio.hpp: make generic with respect to i/o layer.
67e0013 AsioTimer: added expires_after() method.
fc7eaaf Apple CF wrappers: moved CFRunLoop/CFRunLoopSource wrapper to applecrypto/cf, where all other CF wrappers currently reside.
1215912 Revamped Function (our own functor object) to be more flexible.
10fa276 process.hpp: added compile option to avoid async pipe usage.
9e09451 gwv4.hpp: added missing includes
916856d build script: updated Objective-C support when OBJC=1.

git-subtree-dir: OpenVPN Adapter/Vendors/openvpn
git-subtree-split: 4095565b4de2c7d738e728cae989f632100a8ce8

openvpn/asio/asiopolysock.hpp

@@ -139,7 +139,9 @@ namespace openvpn {
 #if !defined(OPENVPN_PLATFORM_WIN)
       virtual void set_cloexec() override
       {
-	SockOpt::set_cloexec(socket.native_handle());
+	const int fd = socket.native_handle();
+	if (fd >= 0)
+	  SockOpt::set_cloexec(fd);
       }
 #endif
 
@@ -207,7 +209,9 @@ namespace openvpn {
 
       virtual void set_cloexec() override
       {
-	SockOpt::set_cloexec(socket.native_handle());
+	const int fd = socket.native_handle();
+	if (fd >= 0)
+	  SockOpt::set_cloexec(fd);
       }
 
       virtual void close() override