In builds without CONFIG_VBOOT_SEPARATE_VERSTAGE, verstage files are
linked directly into the bootblock or the romstage. However, they're
still compiled with a separate "libverstage" source file class, linked
into an intermediate library and then linked into the final destination
stage.

There is no obvious benefit to doing it this way and it's unclear why it
was chosen in the first place... there are, however, obvious
disadvantages: it can result in code that is used by both libverstage
and the host stage to occur twice in the output binary. It also means
that libverstage files have their separate compiler flags that are not
necessarily aligned with the host stage, which can lead to weird effects
like <rules.h> macros not being set the way you would expect. In fact,
VBOOT_STARTS_IN_ROMSTAGE configurations are currently broken on x86
because their libverstage code that gets compiled into the romstage sets
ENV_VERSTAGE, but CAR migration code expects all ENV_VERSTAGE code to
run pre-migration.

This patch resolves these problems by removing the separate library.
There is no more difference between the 'verstage' and 'libverstage'
classes, and the source files added to them are just treated the same
way a bootblock or romstage source files in configurations where the
verstage is linked into either of these respective stages (allowing for
the normal object code deduplication and causing those files to be
compiled with the same flags as the host stage's files).

Tested this whole series by booting a Kevin, an Elm (both with and
without SEPARATE_VERSTAGE) and a Falco in normal and recovery mode.

Change-Id: I6bb84a9bf1cd54f2e02ca1f665740a9c88d88df4
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://review.coreboot.org/18302


Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>