Revert "contrib: rav1e: do the vendoring untar/build during the build phase"

This reverts commit 32512308.

The optional dependency doesn't work.
But in the end we can just create the tarball right after the download failed.
So the rav1e-$(RAV1E_VERSION)-vendor.tar.bz2 is guaranteed to create a usable tarball (or the build will fail).

Ultimately it should be the job of the download_vendor macro to create it if the download fails.

contrib/src/rav1e/rules.mak

@@ -30,7 +30,8 @@ DEPS_rav1e = rav1e-vendor $(DEPS_rav1e-vendor) cargo $(DEPS_cargo)
 
 # rav1e-vendor
 
-rav1e-vendor-build: .sum-rav1e
+rav1e-vendor-build: .cargo
+	$(RM) -R $@
 	mkdir -p $@
 	tar xzfo $(TARBALLS)/rav1e-$(RAV1E_VERSION).tar.gz -C $@ --strip-components=1
 	cd $@ && $(CARGO) vendor --locked rav1e-$(RAV1E_VERSION)-vendor
@@ -40,8 +41,10 @@ rav1e-vendor-build: .sum-rav1e
 	# install $@/SHA512SUMS $(SRC)/rav1e-vendor/SHA512SUMS
 	$(RM) -R $@
 
-$(TARBALLS)/rav1e-$(RAV1E_VERSION)-vendor.tar.bz2:
+$(TARBALLS)/rav1e-$(RAV1E_VERSION)-vendor.tar.bz2: .sum-rav1e
 	-$(call download_vendor,rav1e-$(RAV1E_VERSION)-vendor.tar.bz2,rav1e)
+	# if the vendor tarball doesn't exist yet, we build it
+	if test ! -s "$@"; then $(RM) -R rav1e-vendor-build; $(MAKE) rav1e-vendor-build; fi
 
 .sum-rav1e-vendor: rav1e-$(RAV1E_VERSION)-vendor.tar.bz2
 	touch $@
@@ -50,13 +53,7 @@ rav1e-vendor: rav1e-$(RAV1E_VERSION)-vendor.tar.bz2 .sum-rav1e-vendor
 	$(UNPACK)
 	$(MOVE)
 
-.rav1e-vendor: $(if $(shell test -s "$(TARBALLS)/rav1e-$(RAV1E_VERSION)-vendor.tar.bz2"), rav1e-vendor)
-	# if the vendor tarball doesn't exist yet, we build it and extract it
-	if test ! -s "$(TARBALLS)/rav1e-$(RAV1E_VERSION)-vendor.tar.bz2"; then \
-		$(RM) -R rav1e-vendor-build; \
-		$(MAKE) rav1e-vendor-build; \
-		$(MAKE) rav1e-vendor; \
-	fi
+.rav1e-vendor: rav1e-vendor
 	touch $@
 
 # rav1e