build-style/cargo.sh: add

Manual.md

@@ -734,6 +734,10 @@ The current list of available `build_style` scripts is the following:
 `do_configure()`, `do_build()`, etc., and may overwrite default `do_fetch()` and
 `do_extract()` that fetch and extract files defined in `distfiles` variable.
 
+- `cargo` For packages written in rust that use Cargo for building.
+Configuration arguments (such as `--features`) can be defined in the variable
+`configure_args` and are passed to cargo during `do_build`.
+
 - `cmake` For packages that use the CMake build system, configuration arguments
 can be passed in via `configure_args`. The `cmake_builddir` variable may be
 defined to specify the directory for building under `build_wrksrc` instead of

common/build-style/cargo.sh

@@ -0,0 +1,35 @@
+#
+# This helper is for building rust projects which use cargo for building
+#
+
+do_configure() {
+	mkdir -p .cargo
+	# respect makejobs, do cross stuff
+	cat > .cargo/config <<EOF
+[build]
+jobs = ${makejobs#*j}
+target = "${RUST_TARGET}"
+
+[target.${RUST_TARGET}]
+linker = "${CC}"
+EOF
+}
+
+do_build() {
+	: ${make_cmd:=cargo}
+
+	${make_cmd} build --release ${configure_args}
+}
+
+do_check() {
+	: ${make_cmd:=cargo}
+
+	${make_cmd} test --release ${make_check_args}
+}
+
+do_install() {
+	: ${make_cmd:=cargo}
+
+	${make_cmd} install --root="${DESTDIR}/usr" ${make_install_args}
+	rm "${DESTDIR}"/usr/.crates.toml
+}

common/environment/build-style/cargo.sh

@@ -0,0 +1,10 @@
+hostmakedepends+=" cargo"
+
+if [ "$CROSS_BUILD" ]; then
+	makedepends+=" rust"
+fi
+
+# Use the config we set in do_configure
+export CARGO_HOME="$wrksrc/.cargo"
+
+export PKG_CONFIG_ALLOW_CROSS=1