My compiler doesn't understand -Wno-discard-qualifiers so drop it and
fix the warnings instead. I think it is better to explicitly fix them
anyways instead of just to ignore the discarded const qualifier in
general.
I think the option should be avoided in hand-written code. The warning
is there for a reason: To protect you from possibly overwriting data you
expect to not be modified when passing pointers around.
See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=41215
