[build arm64 broken] unknown directive: toolchain

[thatguyatgithub]

Hi. It looks like build-arm target is broken when building natively on an aarch64 host, but not when cross-building on an amd64 host:

make build-arm
docker buildx build --target=image --platform=linux/arm64 --output=type=docker,name=molnett/cert-manager-webhook-gandi:0.2.2 --tag=molnett/cert-manager-webhook-gandi:latest --build-arg=GO_VERSION=1.20 .
[+] Building 2.4s (11/14)                                                                                                                                                    docker:default
 => [internal] load build definition from Dockerfile                                                                                                                                   0.0s
 => => transferring dockerfile: 769B                                                                                                                                                   0.0s
 => [internal] load .dockerignore                                                                                                                                                      0.0s
 => => transferring context: 255B                                                                                                                                                      0.0s
 => resolve image config for docker.io/docker/dockerfile:1.3                                                                                                                           0.4s
 => CACHED docker-image://docker.io/docker/dockerfile:1.3@sha256:42399d4635eddd7a9b8a24be879d2f9a930d0ed040a61324cfdf59ef1357b3b2                                                      0.0s
 => [internal] load metadata for docker.io/library/golang:1.20-alpine                                                                                                                  0.8s
 => [auth] library/golang:pull token for registry-1.docker.io                                                                                                                          0.0s
 => [base 1/4] FROM docker.io/library/golang:1.20-alpine@sha256:e47f121850f4e276b2b210c56df3fda9191278dd84a3a442bfe0b09934462a8f                                                       0.0s
 => [internal] load build context                                                                                                                                                      0.0s
 => => transferring context: 51.30kB                                                                                                                                                   0.0s
 => CACHED [base 2/4] WORKDIR /go/src/cert-manager-webhook-gandi                                                                                                                       0.0s
 => [base 3/4] COPY go.* .                                                                                                                                                             0.0s
 => ERROR [base 4/4] RUN --mount=type=cache,target=/go/pkg/mod     apk add --no-cache git ca-certificates &&     go mod download                                                       1.0s
------                                                                                                                                                                                      
 > [base 4/4] RUN --mount=type=cache,target=/go/pkg/mod     apk add --no-cache git ca-certificates &&     go mod download:                                                                  
0.262 fetch https://dl-cdn.alpinelinux.org/alpine/v3.19/main/aarch64/APKINDEX.tar.gz                                                                                                        
0.392 fetch https://dl-cdn.alpinelinux.org/alpine/v3.19/community/aarch64/APKINDEX.tar.gz                                                                                                   
0.699 (1/9) Installing brotli-libs (1.1.0-r1)                                                                                                                                               
0.711 (2/9) Installing c-ares (1.27.0-r0)                                                                                                                                                   
0.714 (3/9) Installing libunistring (1.1-r2)
0.727 (4/9) Installing libidn2 (2.3.4-r4)
0.734 (5/9) Installing nghttp2-libs (1.58.0-r0)
0.739 (6/9) Installing libcurl (8.5.0-r0)
0.747 (7/9) Installing libexpat (2.6.2-r0)
0.750 (8/9) Installing pcre2 (10.42-r2)
0.758 (9/9) Installing git (2.43.0-r0)
0.815 Executing busybox-1.36.1-r15.trigger
0.823 OK: 20 MiB in 25 packages
0.956 go: errors parsing go.mod:
0.956 /go/src/cert-manager-webhook-gandi/go.mod:5: unknown directive: toolchain
------
Dockerfile:8
--------------------
   7 |     
   8 | >>> RUN --mount=type=cache,target=/go/pkg/mod \
   9 | >>>     apk add --no-cache git ca-certificates && \
  10 | >>>     go mod download
  11 |     
--------------------
ERROR: failed to solve: process "/bin/sh -c apk add --no-cache git ca-certificates &&     go mod download" did not complete successfully: exit code: 1
make: *** [Makefile:44: build-arm] Error 1