STR: have something like `mk_add_options MOZ_OBJDIR=@TOPSRCDIR@/=obj-@CONFIG_GUESS@` in your mozconfig, and then `./mach build`. My build fails with: 0:06.30 Traceback (most recent call last): 0:06.31 File "/home/keeler/mozilla-central/config/expandlibs_exec.py", line 354, in <module> 0:06.31 exit(main(sys.argv[1:])) 0:06.31 File "/home/keeler/mozilla-central/config/expandlibs_exec.py", line 327, in main 0:06.31 with ExpandArgsMore(args) as args: 0:06.31 File "/home/keeler/mozilla-central/config/expandlibs.py", line 109, in __init__ 0:06.31 self += self._expand(arg) 0:06.31 File "/home/keeler/mozilla-central/config/expandlibs.py", line 125, in _expand 0:06.31 return self._expand_desc(arg) 0:06.31 File "/home/keeler/mozilla-central/config/expandlibs.py", line 135, in _expand_desc 0:06.31 desc = LibDescriptor(f.readlines()) 0:06.31 File "/home/keeler/mozilla-central/config/expandlibs.py", line 94, in __init__ 0:06.31 for key, value in [(s.strip() for s in item.split('=', 2)) for item in content if item.find('=') >= 0]: 0:06.31 ValueError: too many values to unpack 0:06.34 /home/keeler/mozilla-central/config/rules.mk:771: recipe for target 'libxpcomglue.a' failed 0:06.34 gmake[5]: *** [libxpcomglue.a] Error 1 0:06.34 /home/keeler/mozilla-central/config/recurse.mk:71: recipe for target 'xpcom/glue/standalone/target' failed 0:06.34 gmake[4]: *** [xpcom/glue/standalone/target] Error 2 0:06.34 gmake[4]: *** Waiting for unfinished jobs.... I don't know if this is expected to work - I just encountered it while trying to reproduce bug 263212.

(In reply to Dana Keeler [:keeler] (use needinfo?) from comment #0) > 0:06.31 for key, value in [(s.strip() for s in item.split('=', 2)) for > item in content if item.find('=') >= 0]: Try replacing that 2 with a 1.

Thanks - that seems to have fixed that issue (and then it looks like I ran into bug 263212).