get rid of some more gnulinuxisms

to get builds on openbsd going

unexpand.go

@@ -0,0 +1,79 @@
+//go:build tools
+// +build tools
+
+// For unexpand the 4 spaces that the typescript compiler outputs into tabs.
+// Not all unexpand commands implement the -t flag (openbsd).
+package main
+
+import (
+	"bufio"
+	"flag"
+	"fmt"
+	"io"
+	"log"
+	"os"
+)
+
+func xcheckf(err error, format string, args ...any) {
+	if err != nil {
+		log.Fatalf("%s: %s", fmt.Sprintf(format, args...), err)
+	}
+}
+
+func main() {
+	log.SetFlags(0)
+	var width int
+	flag.IntVar(&width, "t", 8, "tab width")
+	flag.Parse()
+	flag.Usage = func() {
+		log.Print("usage: unexpand [-t tabwidth] < input.spaces >output.tabs")
+		flag.PrintDefaults()
+		os.Exit(2)
+	}
+	if flag.NArg() != 0 {
+		flag.Usage()
+	}
+	if width <= 0 {
+		flag.Usage()
+	}
+
+	r := bufio.NewReader(os.Stdin)
+	w := bufio.NewWriter(os.Stdout)
+
+	nspace := 0
+	start := true
+
+	flush := func() {
+		for ; nspace > 0; nspace-- {
+			err := w.WriteByte(' ')
+			xcheckf(err, "write")
+		}
+	}
+	write := func(b byte) {
+		err := w.WriteByte(b)
+		xcheckf(err, "write")
+	}
+
+	for {
+		b, err := r.ReadByte()
+		if err == io.EOF {
+			break
+		}
+		xcheckf(err, "read")
+
+		if start && b == ' ' {
+			nspace++
+			if nspace == width {
+				write('\t')
+				nspace = 0
+			}
+		} else {
+			flush()
+			write(b)
+			start = b == '\n'
+		}
+	}
+	flush()
+	err := w.Flush()
+	xcheckf(err, "flush output")
+}