chore: skip building multi-arch installer for race-enabled build

Go cross-compilation is not quite compatible with Go race detector, as C
toolchain is not cross-compilation ready.

Workaround is really simple: for race-enabled builds, don't build
multi-arch installer image (that is installer image which contains both
amd64 and arm64 Talos artifacts), but build installer artifacts only for
the target arch (skipping cross-compilation).

Signed-off-by: Andrey Smirnov <smirnov.andrey@gmail.com>

Dockerfile

@@ -6,6 +6,7 @@ ARG TOOLS
 ARG IMPORTVET
 ARG PKGS
 ARG EXTRAS
+ARG INSTALLER_ARCH
 
 # Resolve package images using ${PKGS} to be used later in COPY --from=.
 
@@ -466,20 +467,30 @@ RUN chmod +x /installer
 FROM alpine:3.13.5 AS unicode-pf2
 RUN apk add --no-cache --update grub
 
-FROM scratch AS install-artifacts
+FROM scratch AS install-artifacts-amd64
 COPY --from=pkg-grub-amd64 /usr/lib/grub /usr/lib/grub
-COPY --from=pkg-grub-arm64 /usr/lib/grub /usr/lib/grub
-COPY --from=pkg-grub / /
-COPY --from=unicode-pf2 /usr/share/grub/unicode.pf2 /usr/share/grub/unicode.pf2
 COPY --from=pkg-kernel-amd64 /boot/vmlinuz /usr/install/amd64/vmlinuz
-COPY --from=pkg-kernel-arm64 /boot/vmlinuz /usr/install/arm64/vmlinuz
 COPY --from=pkg-kernel-amd64 /dtb /usr/install/amd64/dtb
-COPY --from=pkg-kernel-arm64 /dtb /usr/install/arm64/dtb
 COPY --from=initramfs-archive-amd64 /initramfs.xz /usr/install/amd64/initramfs.xz
+
+FROM scratch AS install-artifacts-arm64
+COPY --from=pkg-grub-arm64 /usr/lib/grub /usr/lib/grub
+COPY --from=pkg-kernel-arm64 /boot/vmlinuz /usr/install/arm64/vmlinuz
+COPY --from=pkg-kernel-arm64 /dtb /usr/install/arm64/dtb
 COPY --from=initramfs-archive-arm64 /initramfs.xz /usr/install/arm64/initramfs.xz
 COPY --from=pkg-u-boot-arm64 / /usr/install/arm64/u-boot
 COPY --from=pkg-raspberrypi-firmware-arm64 / /usr/install/arm64/raspberrypi-firmware
 
+FROM scratch AS install-artifacts-all
+COPY --from=install-artifacts-amd64 / /
+COPY --from=install-artifacts-arm64 / /
+
+FROM install-artifacts-${TARGETARCH} AS install-artifacts-targetarch
+
+FROM install-artifacts-${INSTALLER_ARCH} AS install-artifacts
+COPY --from=pkg-grub / /
+COPY --from=unicode-pf2 /usr/share/grub/unicode.pf2 /usr/share/grub/unicode.pf2
+
 FROM alpine:3.13.5 AS installer
 RUN apk add --no-cache --update \
     bash \

Makefile

@@ -30,6 +30,7 @@ TESTPKGS ?= github.com/talos-systems/talos/...
 RELEASES ?= v0.9.3 v0.10.1
 SHORT_INTEGRATION_TEST ?=
 CUSTOM_CNI_URL ?=
+INSTALLER_ARCH ?= all
 
 VERSION_PKG = github.com/talos-systems/talos/pkg/version
 IMAGES_PKGS = github.com/talos-systems/talos/pkg/images
@@ -54,6 +55,7 @@ ifneq (, $(filter $(WITH_RACE), t true TRUE y yes 1))
 CGO_ENABLED = 1
 GO_BUILDFLAGS += -race
 GO_LDFLAGS += -linkmode=external -extldflags '-static'
+INSTALLER_ARCH = targetarch
 endif
 
 ifneq (, $(filter $(WITH_DEBUG), t true TRUE y yes 1))
@@ -81,6 +83,7 @@ COMMON_ARGS += --build-arg=TAG=$(TAG)
 COMMON_ARGS += --build-arg=ARTIFACTS=$(ARTIFACTS)
 COMMON_ARGS += --build-arg=IMPORTVET=$(IMPORTVET)
 COMMON_ARGS += --build-arg=TESTPKGS=$(TESTPKGS)
+COMMON_ARGS += --build-arg=INSTALLER_ARCH=$(INSTALLER_ARCH)
 COMMON_ARGS += --build-arg=CGO_ENABLED=$(CGO_ENABLED)
 COMMON_ARGS += --build-arg=GO_BUILDFLAGS="$(GO_BUILDFLAGS)"
 COMMON_ARGS += --build-arg=GO_LDFLAGS="$(GO_LDFLAGS)"