Sounds like what we need is a phony makefile target:

.PHONY: all_libs
all_libs: fwlib fwlib2x fwlib20 fwlib21 utillib hostlib tinyhostlib

And then an ebuild use flag to trigger that and copy the libs and headers.

I can add the makefile target easily enough (or review someone else just copy-pasting the above lines into the makefile), but my ebuild foo is not strong.

Thanks rspangler@, I can help with the ebuild changes.

Makefile change: https://chromium-review.googlesource.com/c/chromiumos/platform/vboot_reference/+/1054551

I'm not sure where you want the libraries and headers to go.  I could use $UL_DIR and $UI_DIR and you could override those from the ebuild...

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/overlays/chromiumos-overlay/+/b25b9636c7b74ee8070bc6a01a736410abf421ba

commit b25b9636c7b74ee8070bc6a01a736410abf421ba
Author: Manoj Gupta <manojgupta@google.com>
Date: Fri May 11 02:40:32 2018

vboot_reference: Filter sanitizer flags.

vboot_reference is built with GCC and can't use the sanitizers.

BUG= chromium:841588 
TEST=vboot_reference builds.

Change-Id: Iba75ac0aeba7fef568c4a7acf1036b51a9cdbc3a
Reviewed-on: https://chromium-review.googlesource.com/1053959
Commit-Ready: Manoj Gupta <manojgupta@chromium.org>
Tested-by: Manoj Gupta <manojgupta@chromium.org>
Reviewed-by: Caroline Tice <cmtice@chromium.org>

[modify] https://crrev.com/b25b9636c7b74ee8070bc6a01a736410abf421ba/chromeos/config/env/chromeos-base/vboot_reference

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/overlays/chromiumos-overlay/+/57325dbc7a84ff8423f82f62ff2c53ecd061514b

commit 57325dbc7a84ff8423f82f62ff2c53ecd061514b
Author: Manoj Gupta <manojgupta@google.com>
Date: Wed May 16 07:41:07 2018

vboot_reference: Do not build host tools with USE="fuzzer"

Some of the tools built by vboot_reference fail to build
with sanitizers enabled. So filter them out with USE="fuzzer".

CQ-DEPEND=CL:1060154

BUG= chromium:841588 
TEST=USE="fuzzer" emerge-amd64-generic vboot_reference does not build host tools
TEST=emerge-falco vboot_reference builds all tools.

Change-Id: I21ae2d4b2f8d102d742562c33501f46b4d43508f
Reviewed-on: https://chromium-review.googlesource.com/1060156
Commit-Ready: Manoj Gupta <manojgupta@chromium.org>
Tested-by: Manoj Gupta <manojgupta@chromium.org>
Reviewed-by: Randall Spangler <rspangler@chromium.org>

[modify] https://crrev.com/57325dbc7a84ff8423f82f62ff2c53ecd061514b/chromeos-base/vboot_reference/vboot_reference-9999.ebuild

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/platform/vboot_reference/+/2c3d2c17ee9b379c4e076eaa574ffb671b7e4cb5

commit 2c3d2c17ee9b379c4e076eaa574ffb671b7e4cb5
Author: Manoj Gupta <manojgupta@google.com>
Date: Wed May 16 07:41:06 2018

vboot_reference: Build host tools conditionally.

Some of the tools and utilities in vboot_reference do not build
with sanitizers enabled. To avoid this, do not build them
when NO_BUILD_TOOLS is defined.

CQ-DEPEND=CL:1060156
BUG= chromium:841588 
TEST=USE="fuzzer" emerge-amd64-generic vboot_reference does not build host tools
TEST=emerge-falco vboot_reference builds all tools.

Change-Id: If238c98d4058db20765731237153bc6969a06375
Reviewed-on: https://chromium-review.googlesource.com/1060154
Commit-Ready: Manoj Gupta <manojgupta@chromium.org>
Tested-by: Manoj Gupta <manojgupta@chromium.org>
Reviewed-by: Randall Spangler <rspangler@chromium.org>

[modify] https://crrev.com/2c3d2c17ee9b379c4e076eaa574ffb671b7e4cb5/Makefile