diff -urw firefox-68.0-old/build/moz.configure/rust.configure firefox-68.0/build/moz.configure/rust.configure
--- firefox-68.0-old/build/moz.configure/rust.configure	2019-07-07 15:56:29.345963800 +0000
+++ firefox-68.0/build/moz.configure/rust.configure	2019-07-07 16:19:25.990645334 +0000
@@ -193,12 +193,16 @@
     ambiguous = set()
     per_raw_os = {}
     for t in out:
+        if 'fuchsia' in t: continue
         t = split_triplet(t, allow_unknown=True)
         endianness = t.endianness
         if t.cpu.startswith('thumb') and endianness not in ('big', 'little'):
             endianness = 'little'
         key = (t.cpu, endianness, t.os)
         if key in per_os:
+            # hax to allow Adélie toolchains to work
+            if 'foxkit' in per_os[key].alias:
+                continue
             previous = per_os[key]
             per_raw_os[(previous.cpu, previous.endianness,
                         previous.raw_os)] = previous