Add fortran-int64.eclass to provide utility functions for multilib, int64, static multibuilds. The int64 USE flag is for Fortran 64 bit integer array indices.
Refactor openblas to use the fortran-int64.eclass. Move the virtuals from RDEPEND to PDEPEND to avoid circular dependencies. Specify the pkg-config module name in openblas
Refactor to lapack-reference use the fortran-int64.eclass. Add the virtual to PDEPEND. Call fortran-int64_ensure_blas to check the blas pkg-config file is available, and the blas-int64 pkg-config file if the int64 USE flag is specified. Remove the sed -e /export/s:lapack::g line for CMakeLists.txt, as I do not wish to change this line: "export(TARGETS ${ALL_TARGETS} FILE lapack-targets.cmake)".  Change the addition of the xblas library to the Requires of the pkg-config file to allow for using an int64 build of xblas, by renaming BLAS_PROFNAME to BLAS_REQUIRES then including xblas in the -DBLAS_REQUIRES in src_configure. Try to fix https://github.com/gentoo-science/sci/issues/275 and Bug 524830 - sci-libs/arpack - configure: ld: cannot find -llapack_rs6k by calculating the blas pkg-config file to add to the Requires - needs testing.
multilib int64 multibuild blas-reference
multilib int64 multibuild cblas-reference. int64 fails tests with blas-reference
multilib int64 multibuild xblas. The int64 build may not work though, not tested.
Bump the blas virtual to add int64 supplort for blas-reference.
Bump the cblas virtual to add int64 supplort for cblas-reference.