Fail on linux: sdlx_validate test 22 - "num_rgb([]) is 0x000000"

[kthakore]

Good (verbose:
t/sdlx_validate.t ...............
[...]
ok 19 - list_rgb([0, 0, 0]) is [0, 0, 0]
ok 20 - map_rgb([0, 0, 0], SDL::PixelFormat=SCALAR(0xf29184)) is 0
ok 21 - color([0, 0, 0]) is (0, 0, 0)
ok 22 - num_rgb([]) is 0x000000
ok 23 - list_rgb([]) is [0, 0, 0]
ok 24 - map_rgb([], SDL::PixelFormat=SCALAR(0xf29184)) is 0
[...]

Bad:
t/sdlx_validate.t ...............
All 21 subtests passed

Reports:
http://www.cpantesters.org/cpan/report/0de1c040-06ff-11e0-9ea0-810ec3af36ed