Add musl build based on alpine linux image

.travis.yml

@@ -12,6 +12,15 @@ install:
   - >- # this should only run on linux
     if [ $TRAVIS_OS_NAME = "linux" ]; then
 
+    docker build -t canvas-musl-prebuilt:latest -f docker/Dockerfile.musl .;
+    docker run
+    -e PREBUILD_VERSION="$PREBUILD_VERSION"
+    -e PREBUILD_AUTH="$PREBUILD_AUTH"
+    -e PREBUILD_SLUG="$TRAVIS_REPO_SLUG"
+    -e PREBUILD_NODE_VERSIONS="$PREBUILD_NODE_VERSIONS"
+    -v $(pwd):/build canvas-musl-prebuilt:latest
+    bash -c 'cd /build; export NVM_DIR=$HOME/.nvm; . $HOME/.nvm/nvm.sh; . ci/install.sh linux '"\"$PREBUILD_VERSION\" \"$PREBUILD_CANVAS_VERSION\" \"$PREBUILD_NODE_VERSIONS\"";
+
     docker run
     -e PREBUILD_VERSION="$PREBUILD_VERSION"
     -e PREBUILD_AUTH="$PREBUILD_AUTH"

ci/linux/bundle.sh

@@ -1,4 +1,4 @@
-copies=$(lddtree.sh -l node-canvas/build/Release/canvas.node | sed -r -e '/^\/lib/d' -e '/canvas.node$/d');
+copies=$(lddtree -l node-canvas/build/Release/canvas.node | sed -r -e '/^\/lib/d' -e '/canvas.node$/d');
 
 for so in $copies; do
   cp $so node-canvas/build/Release

ci/linux/node_version.sh

@@ -1,5 +1,5 @@
 VER=$1
 source ~/.nvm/nvm.sh
+source ~/.profile
 nvm use $VER || { nvm install $VER; nvm use $VER; }
 npm install -g node-gyp
-

docker/Dockerfile.musl

@@ -0,0 +1,46 @@
+FROM alpine:3.11
+RUN apk update && apk add --no-cache \
+build-base \
+g++ \
+cairo-dev \
+jpeg-dev \
+pango-dev \
+giflib-dev \
+curl \
+bash \
+coreutils \
+libstdc++ \
+git \
+librsvg-dev \
+lddtree \
+pax-utils \
+zlib-dev \
+libffi-dev \
+libpng-dev \
+libjpeg-turbo-dev \
+fribidi-dev \
+pcre-dev \
+glib-dev \
+freetype-dev \
+harfbuzz-dev \
+expat-dev \
+fontconfig-dev \
+pixman-dev \
+python2 \
+gdk-pixbuf-dev \
+libxml2-dev \
+libcroco-dev
+
+RUN bash -c 'touch ~/.profile'
+
+# https://stackoverflow.com/questions/52196518/could-not-get-uid-gid-when-building-node-docker
+ENV npm_config_unsafe_perm=true
+# Suppress g++ casting warnings that come from node, nan and v8 (https://github.com/nodejs/nan/issues/807)
+ENV CXXFLAGS="-Wno-cast-function-type"
+RUN curl -o- https://raw.githubusercontent.com/creationix/nvm/v0.33.1/install.sh | bash
+
+# Get nvm to work with alpine https://github.com/nvm-sh/nvm/issues/1102#issuecomment-550572252
+RUN bash -c 'echo "NVM_NODEJS_ORG_MIRROR=https://unofficial-builds.nodejs.org/download/release" >> ~/.profile'
+RUN bash -c 'echo "nvm_get_arch() { nvm_echo \"x64-musl\"; }" >> ~/.profile'
+
+RUN bash -c 'source ~/.profile; cd; nvm install v12'