uninative-tarball: Make stamp independent

The uninative tarball only contains nativesdk compoents. It should not get regenerated when MACHINE changes for example. Currently its sstate arch is also incorrect so changing SDKMACHINE results in other variants being removed from the deploy directory.

This patch removes the target architecture dependencies so that deploy artefacts can overlap and it doesn't continually rebuild. This also fixes various autobuilder/release artefact issues we're having as a result of these issues.

index 4ead812..0dad974 100644
@@ -18,6 +18,9 @@ INHIBIT_DEFAULT_DEPS = "1"

 MULTIMACH_TARGET_SYS = "${SDK_ARCH}-nativesdk${SDK_VENDOR}-${SDK_OS}" PACKAGE_ARCH = "${SDK_ARCH}"
+PACKAGE_ARCHS = ""
+TARGET_ARCH = "none"
+TARGET_OS = "none"

 TOOLCHAIN_OUTPUTNAME ?= "${SDK_ARCH}-nativesdk-libc"

@@ -27,16 +30,19 @@ EXCLUDE_FROM_WORLD = "1"

 inherit meta
 inherit populate_sdk
+inherit nopackages

 deltask install
 deltask package
 deltask packagedata
+deltask populate_sysroot

 do_populate_sdk[stamp-extra-info] = "${SDKMACHINE}"

 SDK_DEPENDS += "patchelf-native"

 SDK_PACKAGING_FUNC = ""
+REAL_MULTIMACH_TARGET_SYS = "none"

 fakeroot create_sdk_files() {
  cp ${COREBASE}/scripts/relocate_sdk.py ${SDK_OUTPUT}/${SDKPATH}/