+vgabios_variants := stdvga cirrus vmware qxl isavga
+vgabios_targets := $(subst -isavga,,$(patsubst %,vgabios-%.bin,$(vgabios_variants)))
+pxerom_variants := e1000 eepro100 ne2k_pci pcnet rtl8139 virtio
+pxerom_targets := 8086100e 80861209 10500940 10222000 10ec8139 1af41000
+
+pxe-rom-e1000 efi-rom-e1000 : VID := 8086
+pxe-rom-e1000 efi-rom-e1000 : DID := 100e
+pxe-rom-eepro100 efi-rom-eepro100 : VID := 8086
+pxe-rom-eepro100 efi-rom-eepro100 : DID := 1209
+pxe-rom-ne2k_pci efi-rom-ne2k_pci : VID := 1050
+pxe-rom-ne2k_pci efi-rom-ne2k_pci : DID := 0940
+pxe-rom-pcnet efi-rom-pcnet : VID := 1022
+pxe-rom-pcnet efi-rom-pcnet : DID := 2000
+pxe-rom-rtl8139 efi-rom-rtl8139 : VID := 10ec
+pxe-rom-rtl8139 efi-rom-rtl8139 : DID := 8139
+pxe-rom-virtio efi-rom-virtio : VID := 1af4
+pxe-rom-virtio efi-rom-virtio : DID := 1000
+
+#
+# cross compiler auto detection
+#
+path := $(subst :, ,$(PATH))
+system := $(shell uname -s | tr "A-Z" "a-z")
+
+# first find cross binutils in path
+find-cross-ld = $(firstword $(wildcard $(patsubst %,%/$(1)-*$(system)*-ld,$(path))))
+# then check we have cross gcc too
+find-cross-gcc = $(firstword $(wildcard $(patsubst %ld,%gcc,$(call find-cross-ld,$(1)))))
+# finally strip off path + toolname so we get the prefix
+find-cross-prefix = $(subst gcc,,$(notdir $(call find-cross-gcc,$(1))))
+
+powerpc64_cross_prefix := $(call find-cross-prefix,powerpc64)
+x86_64_cross_prefix := $(call find-cross-prefix,x86_64)
+
+#
+# EfiRom utility is shipped with edk2 / tianocore, in BaseTools/
+#
+# We need that to combine multiple images (legacy bios,
+# efi ia32, efi x64) into a single rom binary.
+#
+# We try to find it in the path. You can also pass the location on
+# the command line, i.e. "make EFIROM=/path/to/EfiRom efirom"
+#
+EFIROM ?= $(shell which EfiRom 2>/dev/null)