Find{BLAS,LAPACK}: Fix OpenBLAS ILP64 support with MSYS2 packages
Typically, ILP64 BLAS libraries are suffixed with 64, but the MSYS2
package provides the ILP64 version of OpenBLAS with a _64 suffix.
Ported from GitHub PR 369.
Typically, ILP64 BLAS libraries are suffixed with 64, but the MSYS2
package provides the ILP64 version of OpenBLAS with a _64 suffix.
Ported from GitHub PR 369.