pass target arch to final image builder as TARGETARCH; use TARGETARCH when generating raw and iso, fallback to build arch; use updated images that read TARGETARCH; ensure grub has EFI for all archs

Signed-off-by: Avi Deitcher <avi@deitcher.net>

tools/grub-dev/Dockerfile

@@ -0,0 +1,53 @@
+# this is really hard to build. Do not change this version unless you must
+FROM linuxkit/alpine:86cd4f51b49fb9a078b50201d892a3c7973d48ec AS grub-build
+
+RUN apk add \
+  automake \
+  make \
+  bison \
+  gettext \
+  flex \
+  gcc \
+  git \
+  libtool \
+  libc-dev \
+  linux-headers \
+  python3 \
+  autoconf
+	
+# because python is not available
+RUN ln -s python3 /usr/bin/python
+	
+ENV GRUB_MODULES="part_gpt fat ext2 iso9660 gzio linux acpi normal cpio crypto disk boot crc64 gpt \
+search_disk_uuid tftp verify xzio xfs video"
+ENV GRUB_COMMIT=2f868ac992be2ae3ab838951aa3e260c045f20f9
+
+COPY patches/* /patches/
+
+WORKDIR /src
+RUN git clone https://github.com/coreos/grub.git grub
+WORKDIR /src/grub
+RUN git checkout -b grub-build ${GRUB_COMMIT}
+RUN  for patch in /patches/*.patch; do \
+    echo "Applying $patch"; \
+    patch -p1 < "$patch"; \
+  done
+
+RUN ./autogen.sh
+
+RUN ./configure --libdir=/grub-lib --with-platform=efi CFLAGS="-Os -Wno-unused-value"
+RUN make -j "$(getconf _NPROCESSORS_ONLN)"
+RUN make install
+RUN case $(uname -m) in \
+  x86_64) \
+    ./grub-mkimage -O x86_64-efi -d /grub-lib/grub/x86_64-efi -o /grub-lib/BOOTX64.EFI -p /EFI/BOOT ${GRUB_MODULES} linuxefi; \
+    ;; \
+  aarch64) \
+    ./grub-mkimage -O arm64-efi -d /grub-lib/grub/arm64-efi -o /grub-lib/BOOTAA64.EFI -p /EFI/BOOT ${GRUB_MODULES}; \
+    ;; \
+  esac
+
+FROM scratch
+ENTRYPOINT []
+WORKDIR /
+COPY --from=grub-build /grub-lib/*.EFI /