Make log decoding build on non-Windows CI

internal/app/codepage_windows.go

@@ -0,0 +1,37 @@
+//go:build windows
+
+package app
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+func decodeWithCodePage(b []byte, codePage uint32) string {
+	if len(b) == 0 {
+		return ""
+	}
+	kernel32 := syscall.NewLazyDLL("kernel32.dll")
+	multiByteToWideChar := kernel32.NewProc("MultiByteToWideChar")
+	n, _, _ := multiByteToWideChar.Call(
+		uintptr(codePage),
+		0,
+		uintptr(unsafe.Pointer(&b[0])),
+		uintptr(len(b)),
+		0,
+		0,
+	)
+	if n == 0 {
+		return ""
+	}
+	buf := make([]uint16, n)
+	multiByteToWideChar.Call(
+		uintptr(codePage),
+		0,
+		uintptr(unsafe.Pointer(&b[0])),
+		uintptr(len(b)),
+		uintptr(unsafe.Pointer(&buf[0])),
+		uintptr(len(buf)),
+	)
+	return utf16ToString(buf)
+}