* gnu/packages/maths.scm (hdf4, hdf4-alt): New variables. * gnu/packages/patches/hdf4-reproducibility.patch: New file. * gnu/packages/patches/hdf4-shared-fortran.patch: New file. * gnu/local.mk (dist_patch_DATA): Add patches. Co-Authored-By: Jeremy Robst <jpro@bas.ac.uk> Signed-off-by: Ludovic Courtès <ludo@gnu.org>