windows: Provide a close(2) that can close both file handles and sockets

src/libstrongswan/utils/windows.c

@@ -331,6 +331,22 @@ static bool check_dontwait(int *flags)
 	return FALSE;
 }
 
+/**
+ * See header
+ */
+#undef close
+int windows_close(int fd)
+{
+	int ret;
+
+	ret = close(fd);
+	if (ret == -1 && errno == EBADF)
+	{	/* Winsock socket? */
+		ret = wserr(closesocket(fd));
+	}
+	return ret;
+}
+
 /**
  * See header
  */

src/libstrongswan/utils/windows.h

@@ -264,6 +264,12 @@ int socketpair(int domain, int type, int protocol, int sv[2]);
  */
 #define ECONNRESET ENXIO
 
+/**
+ * close(2) working for file handles and Winsock sockets
+ */
+#define close windows_close
+int windows_close(int fd);
+
 /**
  * recv(2) with support for MSG_DONTWAIT
  */