musl, and musl-linked scratch gcc image

Makefile

@@ -3,6 +3,10 @@ export SOURCE_DATE_EPOCH = 0
 out/bootstrap.oci.tgz:
 	docker build -t ocirep/bootstrap --output type=oci,dest=$@ packages/bootstrap
 
+out/musl.oci.tgz: \
+	out/musl.oci.tgz
+	docker build -t ocirep/musl --output type=oci,dest=$@ packages/musl
+
 out/gcc.oci.tgz: \
 	out/bootstrap.oci.tgz
 	docker build -t ocirep/gcc --output type=oci,dest=$@ packages/gcc

packages/bootstrap/Dockerfile

@@ -1,5 +1,5 @@
-FROM buildpack-deps@sha256:8465175ca53f8f2e756d069658b3f353bb3732926b1f33f34332cfbf597ad0c0 as build
+FROM alpine@sha256:eece025e432126ce23f223450a0326fbebde39cdf496a85d8c016293fc851978
 
 RUN set -ex; \
-    apt-get update; \
-    apt-get install -y --no-install-recommends flex
+    apk update; \
+    apk add gcc g++ libc-dev make linux-headers

packages/gcc/Dockerfile

@@ -1,3 +1,4 @@
+FROM ocirep/musl:latest as musl
 FROM ocirep/bootstrap:latest as build
 
 ENV GCC_SITE https://mirrors.kernel.org/gnu/gcc
@@ -11,15 +12,19 @@ WORKDIR gcc-${GCC_VERSION}
 RUN set -ex; \
 	./contrib/download_prerequisites; \
 	{ rm *.tar.* || true; }
+
 RUN set -ex; \
 	./configure \
-		--build="x86_64-linux-gnu" \
+		--build="x86_64-linux-musl" \
+		--host="x86_64-linux-musl" \
 		--disable-multilib \
 		--enable-languages=c,c++ \
         --prefix /rootfs \
 	; \
 	make -j "$(nproc)"; \
 	make install-strip
+COPY --from=musl /lib /libmusl
+RUN mv /libmusl/* /rootfs/lib/
 
 FROM scratch
 COPY --from=build /rootfs /

packages/musl/Dockerfile

@@ -0,0 +1,17 @@
+FROM ocirep/bootstrap:latest as build
+
+ENV SRC_SITE http://musl.libc.org
+ENV SRC_VERSION 1.2.4
+ENV SRC_HASH 7a35eae33d5372a7c0da1188de798726f68825513b7ae3ebe97aaaa52114f039
+
+RUN wget ${SRC_SITE}/releases/musl-$SRC_VERSION.tar.gz
+RUN echo "${SRC_HASH} musl-${SRC_VERSION}.tar.gz" | sha256sum -c
+RUN tar -xzf musl-${SRC_VERSION}.tar.gz
+WORKDIR musl-${SRC_VERSION}
+RUN set -ex; \
+	./configure \
+        --prefix=/; \
+	make DESTDIR=/rootfs install;
+
+FROM scratch
+COPY --from=build /rootfs /