Bug#1092781: pyfftw: switch away from cython-legacy

[Chris Hofstaedtler]

Source: pyfftw
Version: 0.13.1-2
Severity: serious
Control: block 1067200 by -1

Your package build-depends or depends on cython-legacy, which was
requested to be removed.
Please switch away from cython-legacy ASAP.

Note that cython-legacy is blocked from re-entering testing, so your
package also cannot enter re-enter testing at the moment.

Best,
Chris (just filing the bugs for this)