Attempt to reduce memory requirements for docker build

Dockerfile

@@ -1,7 +1,13 @@
-FROM golang AS build
+FROM --platform=$BUILDPLATFORM golang:1.25 AS build
+
+ARG TARGETOS TARGETARCH
 
 WORKDIR /app
 
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    gcc-aarch64-linux-gnu libc6-dev-arm64-cross \
+    && rm -rf /var/lib/apt/lists/*
+
 COPY go.mod go.sum ./
 
 RUN go mod download
@@ -9,7 +15,10 @@ RUN go mod download
 COPY zooid zooid
 COPY cmd cmd
 
-RUN CGO_ENABLED=1 GOOS=linux go build -o bin/zooid cmd/relay/main.go
+RUN set -eux; \
+    if [ "$TARGETARCH" = "arm64" ]; then export CC=aarch64-linux-gnu-gcc; fi; \
+    CGO_ENABLED=1 GOOS=$TARGETOS GOARCH=$TARGETARCH \
+    go build -o bin/zooid cmd/relay/main.go
 
 FROM gcr.io/distroless/base-debian12 AS run