gnu: Remove python2-plastid.

* gnu/packages/bioinformatics.scm (python2-plastid): Remove variable.

gnu: Remove python2-twobitreader.

* gnu/packages/bioinformatics.scm (python2-twobitreader): Remove variable.

gnu: python-bbknn: Fix sanity-check phase.

* gnu/packages/bioinformatics.scm (python-bbknn)[arguments]: Add phase
'do-not-fail-to-find-sklearn, which prevents the 'sanity-check phase from
failing.

gnu: python-bbknn: Add missing input.

* gnu/packages/bioinformatics.scm (python-bbknn)[propagated-inputs]: Add
python-scikit-learn.

gnu: velvet: Add missing TeX package.

* gnu/packages/bioinformatics.scm (velvet)[native-inputs]: Add
texlive-fonts-ec.

gnu: velvet: Remove trailing #T.

* gnu/packages/bioinformatics.scm (velvet)[arguments]: Remove trailing #T from
build phases.

gnu: python-bwapy: Remove pre-built object files.

* gnu/packages/bioinformatics.scm (python-bwapy)[source]: Remove all .o files
in a snippet.

gnu: metabat: Remove trailing #T.

* gnu/packages/bioinformatics.scm (metabat)[arguments]: Remove trailing #T
from build phases.

gnu: clapack: Pass -fcommon to compiler.

* gnu/packages/maths.scm (clapack)[arguments]: Set CFLAGS.

gnu: clapack: Remove trailing #T.

* gnu/packages/maths.scm (clapack)[arguments]: Remove trailing #T from build
phases.

gnu: tla2tools: Remove remaining reference to %output.

This is a follow-up to commit 7e6ee16d498f48b7bb74fefe5d3d67c62b5baa9d.

* gnu/packages/java.scm (tla2tools)[arguments]: Remove remaining reference to
%output.

gnu: kraken2: Remove reference to %outputs.

* gnu/packages/bioinformatics.scm (kraken2)[arguments]: Remove reference to
%outputs by using a gexp.

gnu: methyldackel: Remove reference to %outputs.

* gnu/packages/bioinformatics.scm (methyldackel)[arguments]: Remove reference
to %outputs by using a gexp.

gnu: phast: Remove reference to %outputs.

* gnu/packages/bioinformatics.scm (phast)[arguments]: Remove reference to
%outputs by using a gexp.

gnu: libsbml: Remove references to %build-inputs.

* gnu/packages/bioinformatics.scm (libsbml)[arguments]: Remove references to
%build-inputs by using a gexp.

gnu: ataqv: Remove references to %outputs and %build-inputs.

* gnu/packages/bioinformatics.scm (ataqv)[arguments]: Remove references to
%outputs and %build-inputs by using a gexp.

gnu: adapterremoval: Remove reference to %outputs.

* gnu/packages/bioinformatics.scm (adapterremoval)[arguments]: Remove
reference to %outputs by using a gexp.

gnu: bbmap: Remove reference to %build-inputs.

* gnu/packages/bioinformatics.scm (bbmap)[arguments]: Remove reference to
%build-inputs by using a gexp.

gnu: intervaltree: Remove reference to %outputs.

* gnu/packages/bioinformatics.scm (intervaltree)[arguments]: Remove reference
to %outputs by using a gexp.

gnu: biobambam2: Remove reference to %build-inputs.

* gnu/packages/bioinformatics.scm (biobambam2)[arguments]: Remove reference to
%build-inputs by using a gexp.