I erroneously assumed that .mar generation was entirely out-of-process and relied on unpackaging. I now see that's not the case.
When generating the complete .mar for a build that was universal, the universal build should be packaged into the .mar. This is probably as simple as adding a check here:
PACKAGE_DIR = $(DIST)/universal/$(MOZ_PKG_APPNAME)/$(MOZ_APP_DISPLAYNAME).app
PACKAGE_DIR = $(DIST)/$(MOZ_PKG_APPNAME)/$(MOZ_APP_DISPLAYNAME).app
Are any other in-tree changes needed to support AUS?
Created attachment 212993 [details] [diff] [review]
Build universal .mar
This implements my proposed change, which works.
Fixed on trunk.
This must be taken on the branch to produce .mar files for AUS in the universal universe.
Created attachment 213075 [details] [diff] [review]
Checked in on MOZILLA_1_8_BRANCH.
Comment on attachment 213075 [details] [diff] [review]
approved for 1.8.9 branch, a=dveditz for drivers
I hope you don't mind that I checked it in on the 1.8.0 branch instead.