payloads/external: Add support for coreDOOM payload

coreDOOM is a port of DOOM to libpayload, based on the doomgeneric
source port. It renders the game to the coreboot linear framebuffer,
and loads WAD files from CBFS.

Tested with QEMU i440fx/q35 and a Dell Latitude E6400 using the
libgfxinit provided linear framebuffer.

Project page: https://github.com/nic3-14159/coreDOOM

Signed-off-by: Nicholas Chin <nic.c3.14@gmail.com>
Change-Id: Ice0403b003a4b2717afee585f28303c2f5abea5d
Reviewed-on: https://review.coreboot.org/c/coreboot/+/57222
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Paul Menzel <paulepanter@mailbox.org>
Reviewed-by: Martin L Roth <gaumless@tutanota.com>

payloads/external/coreDOOM/Makefile

@@ -0,0 +1,34 @@
+## SPDX-License-Identifier: GPL-2.0-only
+project_git_repo=https://github.com/nic3-14159/coreDOOM.git
+project_dir=coredoom
+
+unexport KCONFIG_AUTOHEADER
+unexport KCONFIG_AUTOCONFIG
+unexport KCONFIG_DEPENDENCIES
+unexport KCONFIG_SPLITCONFIG
+unexport KCONFIG_TRISTATE
+unexport KCONFIG_NEGATIVES
+
+all: coredoom
+
+checkout:
+	test -d coredoom || \
+	    git clone $(project_git_repo) $(project_dir)
+	cd $(project_dir) && \
+	    git checkout libpayload_port
+
+coredoom: libpayload
+	$(MAKE) -C $(project_dir)/doomgeneric
+
+libpayload: checkout
+	cp libpayload-config ../../libpayload/.config && \
+	    cd ../../libpayload && $(MAKE) olddefconfig && $(MAKE) && \
+	    $(MAKE) DESTDIR=../external/coreDOOM/coredoom/doomgeneric install
+
+clean:
+	test -d coredoom && $(MAKE) -C coredoom/doomgeneric clean || exit 0
+
+distclean:
+	rm -rf coredoom
+
+.PHONY: checkout coredoom clean distclean