some fixes to blas/lapack usage in packages (#1852)

* atlas: fix unit test

* openblas: remove symlinks; use lapack_libs.ld_flags in the test

* mkl: fix openmp variant of blas/lapack libs

* intel-parallel-studio: fix openmp variant of blas/lapack libs

* netlib-scalapack: fix blas/lapack for multilib case (e.g. mkl)

* arpack-ng: fix blas/lapack for multilib case (e.g. mkl)

* petsc: explicitly specify blas/lapack

* minor

* cantera: fix blas/lapack usage

* ipopt: fix blas/lapack usage

* netlib-lapack: fix external blas usage

* mfem: fix lapack/blas usage

* superlu-mt: fix blas usage

* flake8 fixes

var/spack/repos/builtin/packages/mfem/package.py

@@ -89,8 +89,7 @@ def install(self, spec, prefix):
         options = ['PREFIX=%s' % prefix]
 
         if '+lapack' in spec:
-            lapack_lib = '-L{0} -llapack -L{1} -lblas'.format(
-                spec['lapack'].prefix.lib, spec['blas'].prefix.lib)
+            lapack_lib = (spec['lapack'].lapack_libs + spec['blas'].blas_libs).ld_flags  # NOQA: ignore=E501
             options.extend([
                 'MFEM_USE_LAPACK=YES',
                 'LAPACK_OPT=-I%s' % spec['lapack'].prefix.include,