In dumb_socketpair(), delete Unix-domain socket path once no longer n…

…eeded

Small follow-up improvement to
https://gitlab.com/openconnect/openconnect/-/merge_requests/320, which made
dumb_socketpair() able to use Unix-domain sockets, on those Windows versions
that support them albeit only with named paths.

This was suggested as a way to prevent the Windows dumb_socketpair()
implementation from leaving behind size-0 files, even if normally only in
temporary directories.

See original suggestion at
microsoft/WSL#4240 (comment).

Signed-off-by: Daniel Lenski <dlenski@gmail.com>

compat.c

@@ -511,6 +511,8 @@ int dumb_socketpair(OPENCONNECT_CMD_SOCKET socks[2], int make_overlapped)
             goto fallback;
         if (connect(socks[0], &a.addr, addrlen) == SOCKET_ERROR)
             goto fallback;
+        if (domain == AF_UNIX)
+            DeleteFile(a.unaddr.sun_path);  // Socket file no longer needed
 
         socks[1] = accept(listener, NULL, NULL);
         if (socks[1] == INVALID_SOCKET)