build: enable maintainer flags when doing distcheck.
build: enable maintainer flags when doing distcheck.

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