Fix #4421: Add -C DIR flag (#4422)

feature: Fix #4421: Add `-C DIR` flag

Signed-off-by: Roger Standridge <9526806+archie2x@users.noreply.github.com>

tests/testing/chdir/chdir.go

@@ -0,0 +1,27 @@
+package main
+
+import (
+	"log"
+	"os"
+	"path/filepath"
+	"runtime"
+)
+
+/*
+Test that this program is 'run' in expected directory. 'run' with expected
+working-directory in 'EXPECT_DIR' environment variable' with{,out} a -C
+argument.
+*/
+func main() {
+	expectDir := os.Getenv("EXPECT_DIR")
+	cwd, err := os.Getwd()
+	if err != nil {
+		log.Fatal(err)
+	}
+	if runtime.GOOS == "windows" {
+		cwd = filepath.ToSlash(cwd)
+	}
+	if cwd != expectDir {
+		log.Fatalf("expected:\"%v\" != os.Getwd():\"%v\"", expectDir, cwd)
+	}
+}