Another place the build system can get source files from is
through an SCM such as Git or Subversion.
In this case, a repository is cloned or checked out.
The
do_fetch
task inside BitBake uses
the SRC_URI
variable and the argument's prefix to determine the correct
fetcher module.
DL_DIR
directory, see the
BB_GENERATE_MIRROR_TARBALLS
variable.
When fetching a repository, BitBake uses the
SRCREV
variable to determine the specific revision from which to
build.