* gnu/packages/bison.scm (bison): Move FLEX to 'inputs', and remove the
hack that turned off its test suite.
* gnu/packages/flex.scm (flex): Add 'bison-for-tests' in 'inputs', and
use that to run the tests.
* gnu/packages/bison.scm (bison): Update to 3.0. Make Perl a native
input. Add a variant of Flex as a native input. Use #:export instead
of 'define-public'.
* gnu/packages/flex.scm (flex): Use #:export instead of 'define-public'.
