Add zigcc wrapper for s390x cross-compilation, including Makefile, tests, and Go module setup.

Author: jiridanek

scripts/zigcc/Makefile

@@ -0,0 +1,21 @@
+.PHONY: build test clean
+
+build: bin/zigcc
+
+# always build for linux and the machine's native architecture
+bin/zigcc: *.go go.mod
+	GOOS=linux go build -o $@ -ldflags="-s -w" -v ./...
+
+test:
+	go test -v ./...
+
+fmt:
+	go fmt ./...
+
+vet:
+	go vet ./...
+
+clean:
+	go clean
+	rm -f bin/*
+	rmdir bin

scripts/zigcc/go.mod

@@ -0,0 +1,3 @@
+module zigcc
+
+go 1.24

scripts/zigcc/zigcc.go

@@ -0,0 +1,56 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+	"syscall"
+)
+
+func processArg0(arg0 string) (string, error) {
+	switch arg0 {
+	case "zig-cc":
+		return "cc", nil
+	case "zig-c++":
+		return "c++", nil
+	default:
+		return "", fmt.Errorf("unknown wrapper name: %s", arg0)
+	}
+}
+
+func processArgs(args []string) []string {
+	newArgs := make([]string, 0, len(args))
+	for _, arg := range args {
+		if strings.HasPrefix(arg, "-Wp,") {
+			newArgs = append(newArgs, strings.Split(arg, ",")[1:]...)
+		} else {
+			newArgs = append(newArgs, arg)
+		}
+	}
+	return newArgs
+}
+
+func main() {
+	arg0 := filepath.Base(os.Args[0])
+	subcommand, err := processArg0(arg0)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Error: %v\n", err)
+		os.Exit(1)
+	}
+
+	newArgs := make([]string, 0, len(os.Args)+4)
+	newArgs = append(newArgs,
+		"/mnt/zig", // Path to the real Zig executable.
+		subcommand,
+		"-target",
+		"s390x-linux-gnu.2.34",
+	)
+	newArgs = append(newArgs, processArgs(os.Args[1:])...)
+
+	env := os.Environ()
+	if err := syscall.Exec(newArgs[0], newArgs, env); err != nil {
+		fmt.Fprintf(os.Stderr, "Error executing zig: %v\n", err)
+		os.Exit(1)
+	}
+}

scripts/zigcc/zigcc_test.go

@@ -0,0 +1,35 @@
+package main
+
+import (
+	"fmt"
+	"reflect"
+	"testing"
+)
+
+func TestProcessWp(t *testing.T) {
+	args := []string{"-Wp,-D_FORTIFY_SOURCE=2"}
+	newArgs := processArgs(args)
+	if !reflect.DeepEqual(newArgs, []string{"-D_FORTIFY_SOURCE=2"}) {
+		t.Fatalf("expected -DFOO=bar, got %v", newArgs)
+	}
+	for _, tc := range []struct {
+		args     []string
+		expected []string
+	}{
+		{
+			args:     []string{"-Wp,-D_FORTIFY_SOURCE=2"},
+			expected: []string{"-D_FORTIFY_SOURCE=2"},
+		},
+		{
+			args:     []string{"-Wp,-DNDEBUG,-D_FORTIFY_SOURCE=2"},
+			expected: []string{"-DNDEBUG", "-D_FORTIFY_SOURCE=2"},
+		},
+	} {
+		t.Run(fmt.Sprint(tc.args), func(t *testing.T) {
+			newArgs := processArgs(tc.args)
+			if !reflect.DeepEqual(newArgs, tc.expected) {
+				t.Fatalf("expected %#v, got %#v", tc.expected, newArgs)
+			}
+		})
+	}
+}