Switch to externally-linked FlexiBLAS on RHEL 9 for compatibility with EPEL R, starting from R 4.3.0. FlexiBLAS defaults to OpenBLAS-OpenMP (and can be used to swap to any other BLAS), so it's not a huge change from the currently used OpenBLAS-pthreads.
R 4.2.3 and below continue to use shared BLAS (OpenBLAS) for backward compatibility.
I didn't change anything for RHEL 8 because EPEL 8 R's new BLAS configuration is no longer swappable, and I figured it was better to keep the flexibility/consistency.
For testing, CI should pass, and I've done some manual testing to confirm that R devel/4.3.0 now links to FlexiBLAS, and R 4.2.3 still links to R's internal BLAS:
Resolves https://github.com/rstudio/r-builds/issues/154
Switch to externally-linked FlexiBLAS on RHEL 9 for compatibility with EPEL R, starting from R 4.3.0. FlexiBLAS defaults to OpenBLAS-OpenMP (and can be used to swap to any other BLAS), so it's not a huge change from the currently used OpenBLAS-pthreads.
R 4.2.3 and below continue to use shared BLAS (OpenBLAS) for backward compatibility.
I didn't change anything for RHEL 8 because EPEL 8 R's new BLAS configuration is no longer swappable, and I figured it was better to keep the flexibility/consistency.
For testing, CI should pass, and I've done some manual testing to confirm that R devel/4.3.0 now links to FlexiBLAS, and R 4.2.3 still links to R's internal BLAS: