multiple fixes

- avoid choking in morestack on i586,
 - fixup dependencies
 - rename rust-cross to internal-rust-cross (in the hope the people are
   less likely to try to inherit it when they shouldn't)
 - enable-local-rust for -target and -cross builds

classes/internal-rust-cross.bbclass

@@ -0,0 +1,17 @@
+inherit cross
+
+# Otherwise we'll depend on what we provide
+INHIBIT_DEFAULT_DEPS = "1"
+
+
+DEPENDS += "virtual/${TARGET_PREFIX}gcc rust-native"
+PROVIDES = "virtual/${TARGET_PREFIX}rust"
+PN = "rust-cross-${TARGET_ARCH}"
+
+## gcc-cross settings
+# INHIBIT_DEFAULT_DEPS = "1"
+# INHIBIT_PACKAGE_STRIP = "1"
+# ARCH_FLAGS_FOR_TARGET += "-isystem${STAGING_DIR_NATIVE}${target_includedir}"
+
+# TODO: use rust-native instead of a snapshot
+EXTRA_OECONF += ""