switch *flags.Spectre {
	default:
		log.Printf("unknown setting -spectre=%s", *flags.Spectre)
		os.Exit(2)
	case "":
		// nothing
	case "index":
		// known to compiler; ignore here so people can use
		// the same list with -gcflags=-spectre=LIST and -asmflags=-spectrre=LIST
	case "all", "ret":
		ctxt.Retpoline = true
	}

	ctxt.Bso = bufio.NewWriter(os.Stdout)
	defer ctxt.Bso.Flush()

<code>R10</code> points to the <code>g</code> (goroutine) structure.
Within assembler source code, this pointer must be referred to as <code>g</code>;
the name <code>R10</code> is not recognized.
</p>

<p>
To make it easier for people and compilers to write assembly, the ARM linker
allows general addressing forms and pseudo-operations like <code>DIV</code> or <code>MOD</code>
that may not be expressible using a single hardware instruction.

	}
}

// fieldPrefix returns the prefix that should be removed from all the
// field names when generating the C or Go code. For generated
// C, we leave the names as is (tv_sec, tv_usec), since that's what
// people are used to seeing in C.  For generated Go code, such as
// package syscall's data structures, we drop a common prefix
// (so sec, usec, which will get turned into Sec, Usec for exporting).

)

func fileFeatures(filename string, needApproval bool) []string {
	bs, err := os.ReadFile(filename)
	if err != nil {
		log.Fatal(err)
	}
	s := string(bs)

	// Diagnose common mistakes people make,
	// since there is no apifmt to format these files.
	// The missing final newline is important for the
	// final release step of cat next/*.txt >go1.X.txt.