fmsg: support temporarily withholding output

Trying to print to a shared stdout is a terrible idea. This change makes it possible to withhold output for the lifetime of the sandbox.

Signed-off-by: Ophestra Umiker <cat@ophivana.moe>

internal/shim/main.go

@@ -134,9 +134,9 @@ func doShim(socket string) {
 			fmsg.VPrintln("wait:", err)
 		}
 		if b.Unwrap().ProcessState != nil {
-			os.Exit(b.Unwrap().ProcessState.ExitCode())
+			fmsg.Exit(b.Unwrap().ProcessState.ExitCode())
 		} else {
-			os.Exit(127)
+			fmsg.Exit(127)
 		}
 	}
 }