Ocaml wants to install its "core" libraries in OCAML_CORE_STDLIB.  That
does not work in a store-based distribution.

A solution was already provided by Nix

    https://github.com/NixOS/nixpkgs/blob/master/pkgs/development/tools/ocaml/findlib/install_topfind.patch

regenerated for Guix.

--- findlib-1.5.3/src/findlib/Makefile	2014-09-16 13:21:46.000000000 +0200
+++ findlib-1.5.3/src/findlib/Makefile.new	2014-10-01 14:30:54.141082521 +0200
@@ -89,7 +89,7 @@
 install: all
 	mkdir -p "$(prefix)$(OCAML_SITELIB)/$(NAME)"
 	mkdir -p "$(prefix)$(OCAMLFIND_BIN)"
-	test $(INSTALL_TOPFIND) -eq 0 || cp topfind "$(prefix)$(OCAML_CORE_STDLIB)"
+	test $(INSTALL_TOPFIND) -eq 0 || cp topfind "$(prefix)$(OCAML_SITELIB)"
 	files=`$(TOP)/tools/collect_files $(TOP)/Makefile.config findlib.cmi findlib.mli findlib.cma topfind.cmi topfind.mli fl_package_base.mli fl_package_base.cmi fl_metascanner.mli fl_metascanner.cmi fl_metatoken.cmi findlib_top.cma findlib.cmxa findlib.a findlib.cmxs findlib_dynload.cma findlib_dynload.cmxa findlib_dynload.a findlib_dynload.cmxs fl_dynload.mli fl_dynload.cmi META` && \
 	cp $$files "$(prefix)$(OCAML_SITELIB)/$(NAME)"
 	f="ocamlfind$(EXEC_SUFFIX)"; { test -f ocamlfind_opt$(EXEC_SUFFIX) && f="ocamlfind_opt$(EXEC_SUFFIX)"; }; \
s/patches/libevent-2.0-CVE-2016-10197.patch'>log</a><a href='/guix/tree/gnu/packages/patches/libevent-2.0-CVE-2016-10197.patch?id=3328132b8740a005c243c6e9f4e339b6e40528d0'>tree</a><a href='/guix/commit/gnu/packages/patches/libevent-2.0-CVE-2016-10197.patch?id=3328132b8740a005c243c6e9f4e339b6e40528d0'>commit</a><a href='/guix/diff/gnu/packages/patches/libevent-2.0-CVE-2016-10197.patch?id=3328132b8740a005c243c6e9f4e339b6e40528d0'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/gnu/packages/patches/libevent-2.0-CVE-2016-10197.patch'>
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<div class='path'>path: <a href='/guix/log/?id=3328132b8740a005c243c6e9f4e339b6e40528d0'>root</a>/<a href='/guix/log/gnu?id=3328132b8740a005c243c6e9f4e339b6e40528d0'>gnu</a>/<a href='/guix/log/gnu/packages?id=3328132b8740a005c243c6e9f4e339b6e40528d0'>packages</a>/<a href='/guix/log/gnu/packages/patches?id=3328132b8740a005c243c6e9f4e339b6e40528d0'>patches</a>/<a href='/guix/log/gnu/packages/patches/libevent-2.0-CVE-2016-10197.patch?id=3328132b8740a005c243c6e9f4e339b6e40528d0'>libevent-2.0-CVE-2016-10197.patch</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/gnu/packages/patches/libevent-2.0-CVE-2016-10197.patch?id=3328132b8740a005c243c6e9f4e339b6e40528d0&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2017-02-02 10:52:45 -0500'>2017-02-02</span></td><td><a href='/guix/commit/gnu/packages/patches/libevent-2.0-CVE-2016-10197.patch?id=e83ef684fc1b490cd54612339a909203d5b94fa4'>gnu: libevent-2.0: Include CVE IDs in patches.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/patches/libevent-2.0-evdns-fix-remote-stack-overread.patch,
gnu/packages/patches/libevent-2.0-evutil-fix-buffer-overflow.patch,
gnu/packages/patches/libevent-2.0-evdns-fix-searching-empty-hostnames.patch:
Rename to ...
* gnu/packages/patches/libevent-2.0-CVE-2016-10195.patch,
gnu/packages/patches/libevent-2.0-CVE-2016-10196.patch,
gnu/packages/patches/libevent-2.0-CVE-2016-10197.patch: ... new files.
* gnu/local.mk (dist_patch_DATA): Adjust accordingly.
* gnu/packages/libevent.scm (libevent-2.0)[sources]: Likewise.
</span></span></td><td>Leo Famulari</td></tr>