create libmodprobe, integrate into first_stage_init

Modprobe functionality is required both within first stage init and also
as a standalone binary. Create a library for this using and extending
the logic in modalias_handler.cpp.

First stage init will attempt to load modules from /lib/modules.

Bug: 129780532
Change-Id: Ie3582358fd839c2f64e1b386b30ed551a86aef5d
diff --git a/libmodprobe/libmodprobe_test.h b/libmodprobe/libmodprobe_test.h
new file mode 100644
index 0000000..a001b69
--- /dev/null
+++ b/libmodprobe/libmodprobe_test.h
@@ -0,0 +1,23 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <string>
+#include <vector>
+
+extern std::vector<std::string> test_modules;
+extern std::vector<std::string> modules_loaded;