[docker] use binary alt-ergo builds

This speeds up the build box build job.

Author: fdupress

scripts/docker/Dockerfile.build

@@ -11,36 +11,19 @@ RUN \
 	opam install --deps-only --confirm-level=unsafe-yes easycrypt && \
 	opam clean
 
-COPY --chmod=0755 --chown=1001:0 docker-parts/alt-ergo bin/run-alt-ergo
-
 ENV PATH="/home/charlie/bin:$PATH"
 
 RUN \
 	version=2.6.3 && \
-	opam switch create --no-switch alt-ergo-${version} ocaml-system && \
-	opam pin     --switch=alt-ergo-${version} add -n alt-ergo ${version} && \
-	opam install --switch=alt-ergo-${version} --deps-only --confirm-level=unsafe-yes alt-ergo && \
-	opam install --switch=alt-ergo-${version} alt-ergo && \
-	opam clean   --switch=alt-ergo-${version} && \
-	ln -s run-alt-ergo ~/bin/alt-ergo-${version}
+  wget -O alt-ergo https://github.com/OCamlPro/alt-ergo/releases/download/v${version}/alt-ergo-v${version}-x86_64-linux-musl && \
+  sudo install -m 0755 alt-ergo /usr/local/bin/alt-ergo-${version} && \
+  rm -f alt-ergo
 
 RUN \
 	version=2.5.4 && \
-	opam switch create --no-switch alt-ergo-${version} ocaml-system && \
-	opam pin     --switch=alt-ergo-${version} add -n alt-ergo ${version} && \
-	opam install --switch=alt-ergo-${version} --deps-only --confirm-level=unsafe-yes alt-ergo && \
-	opam install --switch=alt-ergo-${version} alt-ergo && \
-	opam clean   --switch=alt-ergo-${version} && \
-	ln -s run-alt-ergo ~/bin/alt-ergo-${version}
-
-RUN \
-	version=2.4.3 && \
-	opam switch create --no-switch alt-ergo-${version} ocaml-system && \
-	opam pin     --switch=alt-ergo-${version} add -n alt-ergo ${version} && \
-	opam install --switch=alt-ergo-${version} --deps-only --confirm-level=unsafe-yes alt-ergo && \
-	opam install --switch=alt-ergo-${version} alt-ergo && \
-	opam clean   --switch=alt-ergo-${version} && \
-	ln -s run-alt-ergo ~/bin/alt-ergo-${version}
+  wget -O alt-ergo https://github.com/OCamlPro/alt-ergo/releases/download/v${version}/alt-ergo-v${version}-x86_64-linux-musl && \
+  sudo install -m 0755 alt-ergo /usr/local/bin/alt-ergo-${version} && \
+  rm -f alt-ergo
 
 FROM base-build as main-linux-amd64