Processing directories twice is both pointless and introduces a race condition.
When building the list, ensure duplicates (like "all" and "noarch") are handled
correctly.
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
             arch_list = pkg_archs.split()
         sdk_pkg_archs = self.d.getVar('SDK_PACKAGE_ARCHS', True)
         if sdk_pkg_archs is not None:
-            arch_list += sdk_pkg_archs.split()
+            for a in sdk_pkg_archs.split():
+                if a not in pkg_archs:
+                    arch_list.append(a)
 
         apt_ftparchive = bb.utils.which(os.getenv('PATH'), "apt-ftparchive")
         gzip = bb.utils.which(os.getenv('PATH'), "gzip")