* Adding version 2.4.3 to ViennaRNA
* Replaced tab indent with spaces
Flake8 error correction
* no swig for viennarna v2.4.3 only
* correcting version/argument conditional syntax error
Fixes#4112
This commit extends the support of the AutotoolsPackage methods
`with_or_without` and `enable_or_disable` to bool-valued variants. It
also defines for those functions a convenience short-cut if the
activation parameter is the prefix of a spec (like in
`--with-{pkg}={prefix}`).
This commit also includes:
* Updates to viennarna and adios accordingly: they have been modified to
use `enable_or_disable` and `with_or_without`
* Improved docstrings in `autotools.py`. Raise `KeyError` if name is
not a variant.
