terminal: Just send the pty master fd to receive the selection.

LOL!!1
diff --git a/clients/window.h b/clients/window.h
index 7d6afdc..27811f3 100644
--- a/clients/window.h
+++ b/clients/window.h
@@ -232,8 +232,8 @@
 
 int
 input_offers_mime_type(struct input *input, const char *type);
-int
-input_receive_mime_type(struct input *input, const char *type);
+void
+input_receive_mime_type(struct input *input, const char *type, int fd);
 
 
 #endif