Fixing some warnings on Linux

There were only a few warnings left, so I fixed them and enabled the unused variable warning by removing the "-Wno-unused" flag. Only the -Wno-unused-parameter remains for now (could be removed later).
Review URL: https://codereview.chromium.org/12480002

git-svn-id: http://skia.googlecode.com/svn/trunk/include@8030 2bbb7eff-a529-9590-31e7-b0007b416f81
1 file changed