package/pkg-python: use post-process opts to pass Cargo manifest path

Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Arnout Vandecappelle <arnout@mind.be>

package/pkg-python.mk

@@ -275,14 +275,14 @@ $(2)_DL_ENV = $$(HOST_PKG_CARGO_ENV)
 endif
 ifndef $(2)_CARGO_MANIFEST_PATH
 ifdef $(3)_CARGO_MANIFEST_PATH
-$(2)_DL_ENV += BR_CARGO_MANIFEST_PATH=$$($(3)_CARGO_MANIFEST_PATH)
+$(2)_DOWNLOAD_POST_PROCESS_OPTS += -m$$($(3)_CARGO_MANIFEST_PATH)
 else
 ifneq ($$($(2)_SUBDIR),)
-$(2)_DL_ENV += BR_CARGO_MANIFEST_PATH=$$($(2)_SUBDIR)/Cargo.toml
+$(2)_DOWNLOAD_POST_PROCESS_OPTS += -m$$($(2)_SUBDIR)/Cargo.toml
 endif
 endif
 else
-$(2)_DL_ENV += BR_CARGO_MANIFEST_PATH=$$($(2)_CARGO_MANIFEST_PATH)
+$(2)_DOWNLOAD_POST_PROCESS_OPTS += -m$$($(2)_CARGO_MANIFEST_PATH)
 endif
 endif