Inconsistent lib name suffix between CMake and Make builds with INTERFACE64 #5259

Hi @martin-frbg

When building OpenBLAS with INTERFACE64 enabled:

• In Make-based builds, setting LIBNAMESUFFIX=64_ correctly gives:
  → openblas64_.lib

• But in CMake-based builds, setting both -DINTERFACE64=ON -DLIBNAMESUFFIX=64_ gives:
  → openblas64__64.lib

This is because CMake appends _64 automatically when INTERFACE64 is set, even if LIBNAMESUFFIX is already provided.

If I set LIBNAMESUFFIX=64_, the final name should just be openblas64_.lib, regardless of INTERFACE64.

Can this behavior be aligned with the Make build logic?

Thanks!