Initial, untested

- rust-cross builds
 - cargo-native still broken
 - untested wrappers for rust and cargo provided in rust.bbclass

classes/rust.bbclass

@@ -0,0 +1,68 @@
+def rust_triple(arch, vendor, os, d):
+    if arch.startswith("arm"):
+        vendor = "-unknown"
+        if os.endswith("gnueabi"):
+            os += bb.utils.contains('TUNE_FEATURES', 'callconvention-hard', 'hf', '', d)
+    elif arch.startswith("x86_64"):
+        vendor = "-unknown"
+        if os == "linux":
+            os = "linux-gnu"
+    return arch + vendor + '-' + os
+
+RUST_TARGET_SYS = "${@rust_triple('${TARGET_ARCH}','${TARGET_VENDOR}','${TARGET_OS}', d)}"
+RUST_BUILD_SYS = "${@rust_triple('${BUILD_ARCH}','${BUILD_VENDOR}','${BUILD_OS}', d)}"
+RUST_HOST_SYS = "${@rust_triple('${HOST_ARCH}','${HOST_VENDOR}','${HOST_OS}', d)}"
+
+RUSTC = "rustc"
+RUSTC_ARCHFLAGS += "--target=${RUST_TARGET_SYS} -C linker=${TARGET_PREFIX}gcc\\ ${TARGET_CC_ARCH}"
+
+
+# BUILD_LDFLAGS
+# 	${STAGING_LIBDIR_NATIVE}
+# 	${STAGING_BASE_LIBDIR_NATIVE}
+# BUILDSDK_LDFLAGS
+# 	${STAGING_LIBDIR}
+# 	#{STAGING_DIR_HOST}
+# TARGET_LDFLAGS ?????
+#RUSTC_BUILD_LDFLAGS = "\
+#	--sysroot ${STAGING_DIR_NATIVE} \
+#	-L${STAGING_LIBDIR_NATIVE}	\
+#	-L${STAGING_BASE_LIBDIR_NATIVE}	\
+#"
+
+RUST_PATH_NATIVE="${STAGING_LIBDIR_NATIVE}:${STAGING_BASE_LIBDIR_NATIVE}"
+
+# FIXME: set based on whether we are native vs cross vs buildsdk, etc
+RUST_PATH = "${RUST_PATH_NATIVE}"
+
+CARGO = "cargo"
+
+oe_runrustc () {
+	bbnote ${RUSTC} ${RUSTC_ARCHFLAGS} ${RUSTC_FLAGS} "$@"
+	"${RUSTC}" ${RUSTC_ARCHFLAGS} ${RUSTC_FLAGS} "$@"
+}
+
+oe_cargo_config () {
+	mkdir -p .cargo
+	# FIXME: we currently blow away the entire config because duplicate
+	# sections are treated as a parse error by cargo (causing the entire
+	# config to be silently ignored.
+	# NOTE: we cannot pass more flags via this interface, the 'linker' is
+	# assumed to be a path to a binary. If flags are needed, a wrapper must
+	# be used.
+	cat >.cargo/config <<EOF
+[target.${RUST_TARGET_SYS}]
+ar = "${TARGET_PREFIX}ar"
+linker = "${TARGET_PREFIX}gcc"
+EOF
+}
+
+oe_runcargo_build () {
+	# FIXME: if there is already an entry for this target, in an existing
+	# cargo/config, this won't work.
+	which cargo
+	bbnote ${CARGO} build --target ${RUST_TARGET_SYS} "$@"
+	oe_cargo_config
+	export RUST_PATH="${RUST_PATH}"
+	"${CARGO}" build -v --target "${RUST_TARGET_SYS}" --release "$@"
+}