The specification states that `clEnqueueMapImage` and
`clEnqueueMapBuffer` should return NULL on error. Ensure this is
checked.
This testing gap was caught by a compiler warning about `dataPtr` being
written but not read. With this fix, there are no more
Wunused-but-set-variable warnings in this test, so reenable the warning.
Signed-off-by: Sven van Haastregt <sven.vanhaastregt@arm.com>
Only disable `-Wunused-but-set-variable` for tests that do not compile
cleanly with this warning enabled. This re-enables the warning for
most other tests, so that it can catch any new occurrences.
Signed-off-by: Sven van Haastregt <sven.vanhaastregt@arm.com>
