* gnu/packages/maths.scm (coda): Remove bundled libraries. [source]: Add patch and snippet to remove bundled zlib, pcre and expat. [inputs]: Add system zlib, pcre and expat. * gnu/packages/patches/coda-use-system-libs.patch: New file. * gnu/local.mk (dist_patch_DATA): Add it. Signed-off-by: Ludovic Courtès <ludo@gnu.org>