MISC: add Dockerfiles and helper scripts for CI

Signed-off-by: Stefan Westerfeld <stefan@space.twc.de>

misc/Dockerfile

+FROM gcc:latest
+
+RUN apt-get update && apt-get install -y \
+  libgcrypt20-dev libsndfile1-dev libmpg123-dev libzita-resampler-dev \
+  libfftw3-dev autoconf-archive clang
+
+ADD . /audiowmark
+WORKDIR /audiowmark
+
+RUN misc/build.sh

misc/Dockerfile-arch

+FROM archlinux
+
+RUN pacman -Syu --noconfirm
+RUN pacman -S --noconfirm \
+    gcc clang make automake autoconf pkg-config \
+    libsndfile mpg123 zita-resampler fftw autoconf-archive
+
+ADD . /audiowmark
+WORKDIR /audiowmark
+
+RUN misc/build.sh

misc/build.sh

+#!/bin/bash
+set -Eeuo pipefail
+
+build()
+{
+  if [ -f "./configure" ]; then
+    make uninstall
+    make distclean
+  fi
+  echo "###############################################################################"
+  echo "# BUILD TESTS :"
+  echo "#   CC=$CC CXX=$CXX "
+  echo "#   ./autogen.sh $@"
+  echo "###############################################################################"
+  $CXX --version | sed '/^[[:space:]]*$/d;s/^/#   /'
+  echo "###############################################################################"
+  ./autogen.sh "$@"
+  make -j `nproc` V=1
+  make -j `nproc` check
+  make install
+}
+
+# Tests using gcc
+export CC=gcc CXX=g++
+
+build
+make -j `nproc` distcheck
+
+# Tests clang
+export CC=clang CXX=clang++
+
+build

misc/dbuild.sh

+#!/bin/bash
+set -Eeuo pipefail
+
+docker build -f "misc/Dockerfile" -t audiowmark-dbuild .
+docker build -f "misc/Dockerfile-arch" -t audiowmark-dbuild-arch .