support/download: accept manifest path as a post-process option

Now we have the post-process options, we can use them to pass the
manifest path instead of passing it through an environment variable.

For now, we support both. The environment variable approach will be
removed again later.

Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
Signed-off-by: Arnout Vandecappelle <arnout@mind.be>

support/download/cargo-post-process

@@ -5,10 +5,12 @@ set -e
 # shellcheck source=helpers source-path=SCRIPTDIR
 . "${0%/*}/helpers"
 
-while getopts "n:o:" OPT; do
+manifest="${BR_CARGO_MANIFEST_PATH-Cargo.toml}"
+while getopts "n:o:m:" OPT; do
     case "${OPT}" in
     o)  output="${OPTARG}";;
     n)  base_name="${OPTARG}";;
+    m)  manifest="${OPTARG}";;
     :)  error "option '%s' expects a mandatory argument\n" "${OPTARG}";;
     \?) error "unknown option '%s'\n" "${OPTARG}";;
     esac
@@ -29,7 +31,7 @@ mkdir -p .cargo/
 mkdir -p "${CARGO_HOME}"
 flock "${CARGO_HOME}"/.br-lock \
 cargo vendor \
-    --manifest-path "${BR_CARGO_MANIFEST_PATH-Cargo.toml}" \
+    --manifest-path "${manifest}" \
     --locked VENDOR \
     > .cargo/config