classes: Update classes to match new bitbake class scope functionality

Move classes to classes-global or classes-recipe as appropriate to take
advantage of new bitbake functionality to check class scope/usage.

(From OE-Core rev: f5c128008365e141082c129417eb72d2751e8045)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/classes-recipe/rust.bbclass

@@ -0,0 +1,51 @@
+#
+# Copyright OpenEmbedded Contributors
+#
+# SPDX-License-Identifier: MIT
+#
+
+inherit rust-common
+
+RUSTC = "rustc"
+
+RUSTC_ARCHFLAGS += "--target=${RUST_HOST_SYS} ${RUSTFLAGS}"
+
+def rust_base_dep(d):
+    # Taken from meta/classes/base.bbclass `base_dep_prepend` and modified to
+    # use rust instead of gcc
+    deps = ""
+    if not d.getVar('INHIBIT_DEFAULT_RUST_DEPS'):
+        if (d.getVar('HOST_SYS') != d.getVar('BUILD_SYS')):
+            deps += " rust-native ${RUSTLIB_DEP}"
+        else:
+            deps += " rust-native"
+    return deps
+
+DEPENDS:append = " ${@rust_base_dep(d)}"
+
+# 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${STAGING_BASE_LIBDIR_NATIVE}	\
+#"
+
+# XXX: for some reason bitbake sets BUILD_* & TARGET_* but uses the bare
+# variables for HOST. Alias things to make it easier for us.
+HOST_LDFLAGS  ?= "${LDFLAGS}"
+HOST_CFLAGS   ?= "${CFLAGS}"
+HOST_CXXFLAGS ?= "${CXXFLAGS}"
+HOST_CPPFLAGS ?= "${CPPFLAGS}"
+
+rustlib_suffix="${TUNE_ARCH}${TARGET_VENDOR}-${TARGET_OS}/rustlib/${RUST_HOST_SYS}/lib"
+# Native sysroot standard library path
+rustlib_src="${prefix}/lib/${rustlib_suffix}"
+# Host sysroot standard library path
+rustlib="${libdir}/${rustlib_suffix}"
+rustlib:class-native="${libdir}/rustlib/${BUILD_SYS}/lib"