Add <sys/quota.h>.

It turns out that at least the Nexus 9 kernel is built without CONFIG_QUOTA.
If we decide we're going to mandate quota functionality, I'm happy for us to
be a part of CTS that ensures that happens, but I don't want to be first, so
there's not much to test here other than "will it compile?". The strace
output looks right though.

Bug: http://b/27948821
Bug: http://b/27952303
Change-Id: If667195eee849ed17c8fa9110f6b02907fc8fc04
diff --git a/tests/sys_quota_test.cpp b/tests/sys_quota_test.cpp
new file mode 100644
index 0000000..e23207b
--- /dev/null
+++ b/tests/sys_quota_test.cpp
@@ -0,0 +1,33 @@
+/*
+ * Copyright (C) 2016 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.
+ */
+
+#include <sys/quota.h>
+
+#include <gtest/gtest.h>
+
+TEST(sys_quota, quotactl_dqblk) {
+  // We don't even have kernels with CONFIG_QUOTA enabled right now.
+  // This just tests that we can compile reasonable code.
+  dqblk current;
+  quotactl(QCMD(Q_GETQUOTA, USRQUOTA), "/", getuid(), reinterpret_cast<char*>(&current));
+}
+
+TEST(sys_quota, quotactl_dqinfo) {
+  // We don't even have kernels with CONFIG_QUOTA enabled right now.
+  // This just tests that we can compile reasonable code.
+  dqinfo current;
+  quotactl(QCMD(Q_GETINFO, USRQUOTA), "/", 0, reinterpret_cast<char*>(&current));
+}