build: give into clangs failures and remove -Wunused-but-set-parameter.
build: give into clangs failures and remove -Wunused-but-set-parameter.

This commit message serves to show how disappointed i am with clang trying
to simply be compatibile with gcc and doing a horrible job of it.

GCC forever.

rayyang2000/libbson,4Second2None/libbson_tmp,remicollet/libbson,bjori/libbson,mongodb/libbson,mapr/libbson,paulmelnikow/libbson,paulmelnikow/libbson,derickr/libbson,paulmelnikow/libbson,4Second2None/libbson_tmp,jqk6/libbson,4Second2None/libbson_tmp,Convey-Compliance/libbson,ajdavis/libbson,mongodbinc-interns/libbson,mapr/libbson,rayyang2000/libbson,4Second2None/libbson_tmp,Machyne/libbson,bjori/libbson,ajdavis/libbson,mongodbinc-interns/libbson,ajdavis/libbson,derickr/libbson,mapr/libbson,Machyne/libbson,alexeyvo/libbson,bjori/libbson,paulmelnikow/libbson,rcsanchez97/libbson,rcsanchez97/libbson,Machyne/libbson,jqk6/libbson,Machyne/libbson,mongodbinc-interns/libbson,mongodb/libbson,remicollet/libbson,ksuarz/libbson,mongodb/libbson,rayyang2000/libbson,rayyang2000/libbson,jqk6/libbson,alexeyvo/libbson,ksuarz/libbson,alexeyvo/libbson,jqk6/libbson,Convey-Compliance/libbson,remicollet/libbson,mongodbinc-interns/libbson,derickr/libbson,ksuarz/libbson,rcsanchez97/libbson,remicollet/libbson,Convey-Compliance/libbson,paulmelnikow/libbson,derickr/libbson