btrfs-progs: ci: add 32bit build test on alpine/musl

Add new CI image target based on 32bit Alpine with musl. It's a copy of
musl and requires docker's buildx extension to properly select the
platform.

Signed-off-by: David Sterba <dsterba@suse.com>

ci/ci-build-musl-i386

@@ -0,0 +1,34 @@
+#!/bin/sh
+# Usage: $0 [branch] [configure options]
+# Create source tarball from HEAD or given branch and build it in musl CI
+# environment. Configure options follow branch name that can be empty.
+
+HERE=`pwd`
+if [ -f "configure.ac" ]; then
+	SOURCEDIR=`pwd`
+elif [ -f "../configure.ac" ]; then
+	cd ..
+	SOURCEDIR=`pwd`
+else
+	echo "ERROR: cannot determine source directory from `pwd`"
+	exit 1
+fi
+
+CIIMAGEDIR=ci/images/ci-musl-i386
+BRANCH=${1:-HEAD}
+if [ "$#" -ge 1 ]; then
+	shift
+fi
+HASH=$(git log -1 --format='%h %s' "$BRANCH")
+
+echo "CI: Generate archive from $BRANCH ($HASH)"
+git archive --prefix=btrfs-progs-devel/ -o devel.tar "$BRANCH"
+echo "$BRANCH $HASH" > GITCOMMIT
+tar uvf devel.tar GITCOMMIT
+#rm GITCOMMIT
+gzip --force --best devel.tar
+
+cd "$CIIMAGEDIR"
+cp "$SOURCEDIR/devel.tar.gz" .
+./docker-build
+./docker-run -- ./test-build devel --disable-documentation --disable-backtrace --disable-libudev "$@"

ci/images/ci-musl-i386/Dockerfile

@@ -0,0 +1,19 @@
+FROM alpine:edge
+
+WORKDIR /tmp
+
+RUN apk update
+RUN apk add linux-headers musl-dev util-linux-dev bash
+RUN apk add attr-dev acl-dev e2fsprogs-dev zlib-dev lzo-dev zstd-dev
+RUN apk add autoconf automake make gcc tar gzip clang
+RUN apk add python3 py3-setuptools python3-dev
+RUN apk add libgcrypt-dev libsodium-dev libkcapi-dev
+
+# For downloading fresh sources
+RUN apk add wget
+
+# Only build tests
+COPY ./test-build .
+COPY ./devel.tar.gz .
+
+CMD ./test-build devel --disable-documentation --disable-backtrace --disable-libudev

ci/images/ci-musl-i386/docker-build

@@ -0,0 +1,11 @@
+#!/bin/sh
+# Run from the directory with Dockerfile, directory name should match the image
+# name
+
+prefix=kdave
+image=$(basename `pwd` | tr '[A-Z]' '[a-z]')
+
+# Make sure the file exists as it's required but can be empty. In that case
+# it's downloaded when ./test-build is executed
+touch devel.tar.gz
+docker buildx build --platform linux/386 -t "$prefix/$image" .

ci/images/ci-musl-i386/docker-run

@@ -0,0 +1 @@
+../docker-run

ci/images/ci-musl-i386/test-build

@@ -0,0 +1,22 @@
+#!/bin/sh
+# usage: $0 [branch name] [configure parameters]
+
+urlbase="https://github.com/kdave/btrfs-progs/archive"
+branch=${1:-devel}
+fname="${branch}.tar.gz"
+url="${urlbase}/${fname}"
+
+shift
+
+echo "btrfs-progs build test of branch ${branch}"
+cd /tmp
+if [ -f "$fname" -a -s "$fname" ]; then
+	echo "Found local file $fname, not downloading"
+else
+	echo "Missing or empty tar, downloading devel branch from git"
+	rm -- "$fname"
+	wget "$url" -O "$fname"
+fi
+tar xf "$fname"
+cd "btrfs-progs-$branch"
+ci/build-default "$@"