--- firefox-68.0/build/moz.configure/rust.configure
+++ firefox-68.0/build/moz.configure/rust.configure
@@ -276,13 +276,15 @@
             if rustc_target:
                 break

+        rustc_target = 'armv7-unknown-linux-gnueabihf'
+
         if rustc_target is None:
             die("Don't know how to translate {} for rustc".format(
                 host_or_target.alias))

         # Check to see whether our rustc has a reasonably functional stdlib
         # for our chosen target.
-        target_arg = '--target=' + rustc_target.alias
+        target_arg = '--target=' + rustc_target
         in_fd, in_path = mkstemp(prefix='conftest', suffix='.rs')
         out_fd, out_path = mkstemp(prefix='conftest', suffix='.rlib')
         os.close(out_fd)
@@ -310,7 +312,7 @@
                 a rust std library for that target installed. Try:

                   rustup target add {}
-                '''.format(host_or_target.alias, rustc, rustc_target.alias)))
+                '''.format(host_or_target.alias, rustc, rustc_target)))
             check_cmd_output(*cmd, onerror=failed)
             if not os.path.exists(out_path) or os.path.getsize(out_path) == 0:
                 failed()
@@ -319,7 +321,7 @@
             os.remove(out_path)

         # This target is usable.
-        return rustc_target.alias
+        return rustc_target

     return rust_target