minimal-bootstrap.musl11: always flush stdio

pkgs/os-specific/linux/minimal-bootstrap/musl/1.1.nix

@@ -58,6 +58,8 @@ let
     #   url = "${liveBootstrap}/patches/stdio_flush_on_exit.patch";
     #   hash = "sha256-/z5ze3h3QTysay8nRvyvwPv3pmTcKptdkBIaMCoeLDg=";
     # })
+    # HACK: always flush stdio immediately
+    ./always-flush.patch
     (fetchurl {
       url = "${liveBootstrap}/patches/va_list.patch";
       hash = "sha256-UmcMIl+YCi3wIeVvjbsCyqFlkyYsM4ECNwTfXP+s7vg=";

pkgs/os-specific/linux/minimal-bootstrap/musl/always-flush.patch

@@ -0,0 +1,12 @@
+diff --git src/env/__libc_start_main.c src/env/__libc_start_main.c
+index 8fbe526..9476c22 100644
+--- src/env/__libc_start_main.c
++++ src/env/__libc_start_main.c
+@@ -91,6 +91,7 @@ static int libc_start_main_stage2(int (*main)(int,char **,char **), int argc, ch
+ 	__libc_start_init();
+ 
+ 	/* Pass control to the application */
++	setbuf(stdout, NULL);
+ 	exit(main(argc, argv, envp));
+ 	return 0;
+ }