verify all C files are distributed
verify all C files are distributed

Catch mistakes like CDRIVER-2071.

rcsanchez97/libbson,bjori/libbson,mapr/libbson,mapr/libbson,rcsanchez97/libbson,mongodb/libbson,bjori/libbson,ajdavis/libbson,mongodb/libbson,mongodb/libbson,ajdavis/libbson,rcsanchez97/libbson,ajdavis/libbson,bjori/libbson,mapr/libbson