Add separatedebug feature

When separatedebug is set in FEATURES, produce the debug symbols in a separate
The resulting tarball is stored in PKGDIR with the extension .debug.tbz2.

TEST=`FEATURES=separatedebug emerge-gizmo metrics` works.
/build/gizmo/packages/chromeos-base/metrics-0.0.1-r365.debug.tbz2 is created.
TEST=`emerge-gizmo metrics` works.
TEST=trybot run on daisy, link, gizmo, chromiumos-sdk, duck, lumpy-incremental.

Change-Id: I280cb9682fba1c6cd27f7b4825c1b331dc4729be
Reviewed-by: Zac Medico <>
Tested-by: Zac Medico <>
Reviewed-by: Bertrand Simonnet <>
Commit-Queue: Bertrand Simonnet <>
5 files changed