build: make passing an incorrect pointer type a hard error

build: make passing an incorrect pointer type a hard error

More or less any of this issue pointed out by the compiler is
a coding error. Make sure we flag it and bail loudly.

v2: - apply the change to autotools and scons as well (Emil)
    - C++ doesn't need this, it's already an error and the flag
      doesn't exist (Gert)
v3: - drop scons, flags are not checked so until someone adds that
      functionality we can't have this.

Signed-off-by: Eric Engestrom <eric.engestrom@intel.com>
Reviewed-by: Dylan Baker <dylan@pnwbakers.com> # v1
Reviewed-by: Emil Velikov <emil.velikov@collabora.com> # v1
[Emil: apply the same change to autotools and scons]
Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
Reviewed-by: Eric Anholt <eric@anholt.net>