Strip trailing slashes when checking for directories on Windows.

Author: cr1901

kernel/io.cc

@@ -251,7 +251,15 @@ bool check_is_directory(const std::string& dirname)
 {
 #if defined(_WIN32)
 	struct _stat info;
-	if (_stat(dirname.c_str(), &info) != 0)
+	auto dirname_ = dirname;
+
+	/* On old versions of Visual Studio and current versions on MinGW,
+	   _stat will fail if the path ends with a trailing slash. */
+	if (dirname.back() == '/' || dirname.back() == '\\') {
+		dirname_ = dirname.substr(0, dirname.length() - 1);
+	}
+
+	if (_stat(dirname_.c_str(), &info) != 0)
 	{
 		return false;
 	}