Syntastic not working for more than one directory deep

[calind]

If I edit the file ./hello.nim syntastic works perfectly, but if I edit ./test/hello_test.nim and vim CWD is ./ syntastic won't work for ./test/hello_test.nim.

I guess that this has something to do with the fact that nim check --hints:off test/hello_test.nim outputs
hello_test.nim(5, 1) Error: value of type 'bool' has to be discarded
instead of
test/hello_test.nim(5, 1) Error: value of type 'bool' has to be discarded
and this somehow confuses buffers.