* Add variants to petsc
This PR adds the follolwing variants to the petsc package
- gmp
- jpeg
- libpng
- giflib
- mpfr
- netcdf
- pnetcdf (parallel-netcdf)
- moab
- eigen
- random123
- exodusii
- mstk
- cgns
- memkind
- muparser
- p4est
- saws
- libyaml
- zstd
* Fix flake8 errors
* Additional changes to Petsc recipe
This commit addresses the issues with dependencies that were brought up
in the comments. There are also a few other enhancements.
- the language of the new variant descriptions was changed to be more
consistent with what was already in the recipe
- an explicit '+mpi' was added to the depends_on('hypre...') directives
- an explicit '+mpi' was added to the depends_on('trilinos...')
directives
- the run time error checking for '~mpi' was replaced with 'conflicts()'
directives that will cause the install to fail sooner
- additional variants that were 'parallel only' were added to the '~mpi'
check
* Set the '~mpi`' conflicts msg to a variable
023a057f20