Fix LAPACK functionality detection from static OpenBLAS (#46710)
Summary:
BLAS `sgemm_` only depends on pthreads, but LAPACK `cheev_` also depends on libm
Pull Request resolved: https://github.com/pytorch/pytorch/pull/46710
Reviewed By: walterddr
Differential Revision: D24476082
Pulled By: malfet
fbshipit-source-id: e0b91116f18bbcdabb1f99c2ec9d98283df4393f
