Turn on -Wall for recovery modules

Turn on -Wall for all modules. Also remove the obsolete file_cmp() in
apply_patch test and now() in wear_ui.

The only exception is lib_edify due to the unused functions in the
intermediate cpp files generated from the lex files. It will be handled
in a seperate CL.

Bug: 64939312
Test: mma, unit tests pass
Change-Id: Ic53f76b60b6401ab20db3d98130d674c08e3702f