Fix hematite recipe

recipes/hematite/recipe.sh

-GIT=https://gitlab.redox-os.org/redox-os/hematite.git
-GIT_UPSTREAM=https://github.com/PistonDevelopers/hematite.git
-BUILD_DEPENDS=(llvm mesa zlib)
-BRANCH=redox
-
-function recipe_build {
-    sysroot="$(realpath ../sysroot)"
-    cp -p "$ROOT/Xargo.toml" "Xargo.toml"
-    set -x
-    xargo rustc --target "$TARGET" --release ${CARGOFLAGS} \
-        -- \
-        -L "${sysroot}/lib" \
-        -C link-args="$("${PKG_CONFIG}" --libs osmesa) -lglapi -lz -lstdc++ -lc -lgcc"
-    set +x
-    skip=1
-}

recipes/hematite/recipe.toml

+[source]
+git = "https://gitlab.redox-os.org/redox-os/hematite.git"
+branch = "redox"
+upstream = "https://github.com/PistonDevelopers/hematite.git"
+
+[build]
+template = "custom"
+dependencies = [
+    "llvm",
+    "mesa",
+    "zlib"
+]
+script = """
+cargo rustc \
+    --target "$TARGET" \
+    --release \
+    --manifest-path "${COOKBOOK_SOURCE}/Cargo.toml" \
+    -- \
+    -L "${COOKBOK_SYSROOT}/lib" \
+    -C link-args="-Wl,-Bstatic $("${TARGET}-pkg-config" --libs osmesa) -lz -lstdc++ -lc -lgcc"
+mkdir -pv "${COOKBOOK_STAGE}/bin"
+cp -v "target/${TARGET}/release/hematite" "${COOKBOOK_STAGE}/bin/hematite"
+"""