gnu: clisp: Update to 2.49.92.

* gnu/packages/lisp.scm (clisp): Update to 2.49.92.
[source]: Switch to git-fetch. Remove unneeded patch.
[arguments]: Remove '--enable-portability' flag, add CFLAGS for
armhf-linux. Update list of files needing substitutions in custom
'patch-sh-and-pwd phase.
[home-page]: Update to new home-page.
* gnu/packages/patches/clisp-glibc-2.26.patch: Remove file.
& gnu/local.mk (dist_patch_DATA): Remove it.