Build libgc in alpine image to enable MT builds (#63)

Co-authored-by: Caspian Baska <email@caspian.computer>

Author: Blacksmoke16

docker/Makefile

@@ -13,11 +13,14 @@ CRYSTAL_TARGZ ?=     ## Which crystal.tar.gz file to install in docker images (a
 DOCKER_TAG ?=	     ## How to tag the docker image (examples: `0.27.2`, `nightly20190307`). `-build` will be appended for build images.
 DOCKER_REPOSITORY ?= ## Docker hub repository to commit image
 
+GC_VERSION = v8.0.4
+LIBATOMIC_OPS_VERSION = v7.6.10
+
 OUTPUT_DIR := build
 BUILD_CONTEXT := $(CURDIR)/build-context
 BUILD_ARGS_UBUNTU64 := --build-arg crystal_deb=crystal.deb $(BUILD_CONTEXT)/ubuntu64 --build-arg base_docker_image=ubuntu:focal
 BUILD_ARGS_UBUNTU32 := --build-arg crystal_deb=crystal.deb $(BUILD_CONTEXT)/ubuntu32 --build-arg base_docker_image=i386/ubuntu:bionic
-BUILD_ARGS_ALPINE := --build-arg crystal_targz=crystal.tar.gz $(BUILD_CONTEXT)/alpine
+BUILD_ARGS_ALPINE := --build-arg crystal_targz=crystal.tar.gz $(BUILD_CONTEXT)/alpine --build-arg gc_version=$(GC_VERSION) --build-arg libatomic_ops_version=$(LIBATOMIC_OPS_VERSION)
 DOCKER_TAG_UBUNTU := $(DOCKER_REPOSITORY):$(DOCKER_TAG)
 DOCKER_TAG_ALPINE := $(DOCKER_REPOSITORY):$(DOCKER_TAG)-alpine
 
@@ -53,6 +56,8 @@ $(BUILD_CONTEXT)/ubuntu64: ubuntu.Dockerfile $(BUILD_CONTEXT)/ubuntu64/crystal.d
 
 $(BUILD_CONTEXT)/alpine: alpine.Dockerfile $(BUILD_CONTEXT)/alpine/crystal.tar.gz
 	cp alpine.Dockerfile $@/Dockerfile
+	mkdir $@/files/
+	cp ../linux/files/feature-thread-stackbottom-upstream.patch $@/files/feature-thread-stackbottom-upstream.patch
 
 %/crystal.deb:
 	mkdir -p $(shell dirname $@)

docker/alpine.Dockerfile

@@ -3,11 +3,33 @@ FROM alpine:3.13 as runtime
 RUN \
   apk add --update --no-cache --force-overwrite \
     # core dependencies
-    gc-dev gcc gmp-dev libatomic_ops libevent-static musl-dev pcre-dev \
+    gcc gmp-dev libevent-static musl-dev pcre-dev \
     # stdlib dependencies
     libxml2-dev openssl-dev openssl-libs-static tzdata yaml-static zlib-static \
     # dev tools
-    make git
+    make git \
+    # build libgc dependencies
+    autoconf automake libtool patch
+
+# Build libgc
+ARG gc_version
+ARG libatomic_ops_version
+COPY files/feature-thread-stackbottom-upstream.patch /tmp/
+RUN git clone https://github.com/ivmai/bdwgc \
+ && cd bdwgc \
+ && git checkout ${gc_version} \
+ && git clone https://github.com/ivmai/libatomic_ops \
+ && (cd libatomic_ops && git checkout ${libatomic_ops_version}) \
+ \
+ && patch -p1 < /tmp/feature-thread-stackbottom-upstream.patch \
+ \
+ && ./autogen.sh \
+ && ./configure --disable-debug --disable-shared --enable-large-config \
+ && make -j$(nproc) CFLAGS=-DNO_GETCONTEXT \
+ && make install
+
+# Remove build tools from image now that libgc is built
+RUN apk del -r --purge autoconf automake libtool patch
 
 ARG crystal_targz
 COPY ${crystal_targz} /tmp/crystal.tar.gz