* gnu/packages/algebra.scm (symmetrica): New variable. * gnu/packages/patches/symmetrica-bruch.patch: * gnu/packages/patches/symmetrica-int32.patch: * gnu/packages/patches/symmetrica-return_values.patch: * gnu/packages/patches/symmetrica-sort_sum_rename.patch: New files. * gnu/local.mk (dist_patch_DATA): Add patches.