kernel: get rid of custom build recipe in favor of the kernel Makefile

recipes/core/kernel/recipe.toml

@@ -4,26 +4,7 @@ git = "https://gitlab.redox-os.org/redox-os/kernel.git"
 [build]
 template = "custom"
 script = """
-export RUST_TARGET_PATH="${COOKBOOK_SOURCE}/targets"
-ARCH="$(echo "${GNU_TARGET}" | cut -d - -f1)"
-cargo rustc \
-	--bin kernel \
-	--manifest-path "${COOKBOOK_SOURCE}/Cargo.toml" \
-	--target "${COOKBOOK_SOURCE}/targets/${ARCH}-unknown-kernel.json" \
-	--release \
-	-Z build-std=core,alloc \
-	-- \
-	-C link-arg=-T -Clink-arg="${COOKBOOK_SOURCE}/linkers/${ARCH}.ld" \
-	-C link-arg=-z -Clink-arg=max-page-size=0x1000 \
-	--emit link="${PWD}/kernel.all"
-"${GNU_TARGET}-objcopy" \
-	--only-keep-debug \
-	kernel.all \
-	kernel.sym
-"${GNU_TARGET}-objcopy" \
-	--strip-debug \
-	kernel.all \
-	kernel
+make -f ${COOKBOOK_SOURCE}/Makefile
 mkdir -v "${COOKBOOK_STAGE}/boot"
 cp -v kernel "${COOKBOOK_STAGE}/boot"
 """