1409945 - Inconsistency dealing with mozconfig when doing non-top-level builds

Status: NEW

(Firefox Build System :: General, defect)

Description

[Mike Hommey [:glandium]]

STR:
- Get a one-click-loaner for a linux64 opt build
- Open a shell
- Wait for the build to finish (I usually follow the live log from inspecting the corresponding task or look at top in the shell)
- Once the build is finished, check the build-id of some .so, e.g.
  objdump -s -j .note.gnu.build-id /builds/worker/workspace/build/src/obj-firefox/config/external/lgpllibs/liblgpllibs.so
- Remove that .so e.g.
  rm /builds/worker/workspace/build/src/obj-firefox/config/external/lgpllibs/liblgpllibs.so
- Rebuild it with:
  cd /builds/worker/workspace/build/src
  MOZ_AUTOMATION=1 MOZ_OBJDIR=obj-firefox ./mach build config/external/lgpllibs/target
- Observe the build-id for that library again, it's different.
- Remove it again.
- Try again with:
  MOZ_AUTOMATION=1 MOZ_OBJDIR=obj-firefox ./mach build
- The build-id is back to the original one.

The reason is that .mozconfig sets PATH, and in the latter case, we use that PATH, which means we use the ld that comes with our gcc toolchain package. In the ./mach config path case, we don't get PATH from .mozconfig, and use the system ld.