build: progress towards bundled libbson for fallback.
build: add libbson submodule.
build: more autotools progress.
build: more build work.
build: init submodule from autogen.sh.
libbson: bump submodule libbson version.
libbson: bump
build: work in progress on libbson submodule.
build: call libbson autogen.sh during mongo-c-driver autogen.sh.
build: wip on libbson submodule building.
build: fix some invalid uses of top_builddir/top_srcdir
build: bump libbson from master.
build: bump libbson.
build: remove old style include for libbson.
build: SUBDIRS into libbson if needed.
build: prefix mongoc sources with src/
build: define BSON_LIBS and BSON_CFLAGS with bundled libbson.
build: just use AC_SUBST, no need to define -D preprocessor.
build: more bundled progress.
build: printf not needed for header.