fixes CamlGI.o installation issue (opam-repository issue #410)
Merge branch 'pr' of https://github.com/camlspotter/opam-repository into pr
Merge remote-tracking branch 'upstream/master' into pr
typo CamlGI.o => CamlGI.a
Merge pull request #412 from camlspotter/pr

CamlGI installation workaround (See #410)