add rust buildsystem.

Makefile

@@ -5,5 +5,6 @@ RPMSCRIPTDIR ?= $(PREFIX)/lib/rpm/rust-rpm-macros
 .PHONY: install
 install:
 	install -D -m644 macros.buildsystem.rustcrates $(DESTDIR)$(RPMMACRODIR)/macros.buildsystem.rustcrates
+	install -D -m644 macros.buildsystem.rust $(DESTDIR)$(RPMMACRODIR)/macros.buildsystem.rust
 	install -D -m644 macros.rust $(DESTDIR)$(RPMMACRODIR)/macros.rust
 	install -D -m755 rustcrates-gen-feature-specparts.sh $(DESTDIR)$(RPMSCRIPTDIR)/rustcrates-gen-feature-specparts.sh

macros.buildsystem.rust

@@ -0,0 +1,22 @@
+
+# Example buildsystem for rust crates
+%buildsystem_rust_prep() %{expand:\
+  %autosetup -a -C -p1 %* \
+  mkdir -p ~/.cargo \
+  cat > ~/.cargo/config.toml <<EOF\
+[source.crates-io]\
+replace-with = "system-registry"\
+\
+[source.system-registry]\
+directory = "/usr/share/cargo/registry"\
+EOF\
+  rm -rf Cargo.lock \
+}
+%buildsystem_rust_conf() %nil
+%buildsystem_rust_build() %{expand:\
+  cargo build --release \
+}
+%buildsystem_rust_install() %{expand:\
+  %{rust_install_crate} \
+}
+%buildsystem_rust_check() %nil