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/superlu-mt/package.py

@@ -86,7 +86,7 @@ def configure(self, spec):
         if '+blas' in spec:
             config.extend([
                 'BLASDEF    = -DUSE_VENDOR_BLAS',
-                'BLASLIB    = -L{0} -lblas'.format(spec['blas'].prefix.lib)
+                'BLASLIB    = {0}'.format(spec['blas'].blas_libs.ld_flags)
             ])
         else:
             config.append('BLASLIB    = ../lib/libblas$(PLAT).a')