Dockerfile

FROM --platform=$BUILDPLATFORM tonistiigi/xx:llvm AS build
ARG TARGETPLATFORM
WORKDIR /src
COPY hello.c .
RUN clang -static -o /hello hello.c

FROM scratch
ARG TARGETPLATFORM
ENV WHOAMI=$TARGETPLATFORM
COPY --from=build /hello .
ENTRYPOINT ["/hello"]

hello.c

#include <stdlib.h>
#include <stdio.h>
 
int main()
{
  printf("Hello world, I am %s!", getenv("WHOAMI"));
  return 0;
}