Fix "Can't use getmntent or getmntinfo to check for mounted filesystems!" warning.

We do have <mntent.h> and setmntent(3).

Also silence unused parameter warnings; C programmers don't care, so
upstream is unlikely to fix that.

Bug: N/A
Test: builds
Change-Id: I57db0cca68a617913e21c2ef7b6613cd1183d7c5
2 files changed