roms: add the edk2 project as a git submodule

The roms/edk2 submodule can help with three goals:
- build the OVMF and ArmVirtQemu virtual UEFI firmware platforms (to be
  implemented later),
- build the EfiRom tool on the fly, which is used in roms/Makefile, for
  building the "efirom" target,
- build UEFI test applications (to be run in guests), for qtest support.

Edk2 commit 85588389222a3636baf0f9ed8227f2434af4c3f9 stands for the latest
"stable tag", namely "edk2-stable201811".

The edk2 repository tracks some binary files that should not be removed by
QEMU's top-level "make clean"; exempt the full pathnames from the "find"
command.

Cc: "Michael S. Tsirkin" <[email protected]>
Cc: Ard Biesheuvel <[email protected]>
Cc: Gerd Hoffmann <[email protected]>
Cc: Igor Mammedov <[email protected]>
Cc: Philippe Mathieu-Daudé <[email protected]>
Cc: Shannon Zhao <[email protected]>
Signed-off-by: Laszlo Ersek <[email protected]>
Reviewed-by: Gerd Hoffmann <[email protected]>
Message-Id: <[email protected]>
Reviewed-by: Igor Mammedov <[email protected]>
Reviewed-by: Michael S. Tsirkin <[email protected]>
Signed-off-by: Michael S. Tsirkin <[email protected]>
Reviewed-by: Philippe Mathieu-Daudé <[email protected]>
Tested-by: Philippe Mathieu-Daudé <[email protected]>

.gitmodules

@@ -49,3 +49,6 @@
 [submodule "tests/fp/berkeley-softfloat-3"]
 	path = tests/fp/berkeley-softfloat-3
 	url = https://github.com/cota/berkeley-softfloat-3
+[submodule "roms/edk2"]
+	path = roms/edk2
+	url = https://github.com/tianocore/edk2.git

Makefile

@@ -607,7 +607,11 @@ clean:
 	rm -f config.mak op-i386.h opc-i386.h gen-op-i386.h op-arm.h opc-arm.h gen-op-arm.h
 	rm -f qemu-options.def
 	rm -f *.msi
-	find . \( -name '*.so' -o -name '*.dll' -o -name '*.mo' -o -name '*.[oda]' \) -type f -exec rm {} +
+	find . \( -name '*.so' -o -name '*.dll' -o -name '*.mo' -o -name '*.[oda]' \) -type f \
+		! -path ./roms/edk2/ArmPkg/Library/GccLto/liblto-aarch64.a \
+		! -path ./roms/edk2/ArmPkg/Library/GccLto/liblto-arm.a \
+		! -path ./roms/edk2/BaseTools/Source/Python/UPT/Dll/sqlite3.dll \
+		-exec rm {} +
 	rm -f $(filter-out %.tlb,$(TOOLS)) $(HELPERS-y) qemu-ga TAGS cscope.* *.pod *~ */*~
 	rm -f fsdev/*.pod scsi/*.pod
 	rm -f qemu-img-cmds.h