Build BABASHKA_STATIC with musl C library (#828)

* Build BABASHKA_STATIC with musl C library

Based on https://github.com/babashka/pod-babashka-aws/pull/37.

This is the recommended way to build static binaries with GraalVM by the
documentation and multiple issues on GitHub. See:

- https://www.graalvm.org/reference-manual/native-image/StaticImages/
- oracle/graal#571 (comment)

The reason that building a statically binary with glibc is complicated
is explained in the glib documentation:

https://sourceware.org/glibc/wiki/FAQ#Even_statically_linked_programs_need_some_shared_libraries_which_is_not_acceptable_for_me.__What_can_I_do.3F

* Bring back zlib1g-dev

Seems it is necessary for the non-static build.

.circleci/config.yml

@@ -105,7 +105,7 @@ jobs:
           name: Install native dev tools
           command: |
             sudo apt-get update
-            sudo apt-get -y install gcc g++ zlib1g-dev
+            sudo apt-get -y install g++ zlib1g-dev
       - run:
           name: Download GraalVM
           command: |

Dockerfile

@@ -1,12 +1,13 @@
 FROM clojure:lein-2.9.1 AS BASE
 
+ENV DEBIAN_FRONTEND=noninteractive
 RUN apt update
-RUN apt install --no-install-recommends -yy curl unzip build-essential zlib1g-dev
+RUN apt install --no-install-recommends -yy curl unzip build-essential zlib1g-dev sudo
 WORKDIR "/opt"
 RUN curl -sLO https://github.com/graalvm/graalvm-ce-builds/releases/download/vm-21.0.0/graalvm-ce-java11-linux-amd64-21.0.0.tar.gz
 RUN tar -xzf graalvm-ce-java11-linux-amd64-21.0.0.tar.gz
 
-ARG BABASHKA_XMX="-J-Xmx3g"
+ARG BABASHKA_XMX="-J-Xmx4500m"
 
 ENV GRAALVM_HOME="/opt/graalvm-ce-java11-21.0.0"
 ENV JAVA_HOME="/opt/graalvm-ce-java11-21.0.0/bin"
@@ -31,6 +32,7 @@ ARG BABASHKA_FEATURE_HSQLDB=
 ARG BABASHKA_FEATURE_ORACLEDB=
 ARG BABASHKA_FEATURE_DATASCRIPT=
 ARG BABASHKA_FEATURE_LANTERNA=
+ARG BABASHKA_STATIC=
 ENV BABASHKA_LEAN=$BABASHKA_LEAN
 ENV BABASHKA_FEATURE_CORE_ASYNC=$BABASHKA_FEATURE_CORE_ASYNC
 ENV BABASHKA_FEATURE_CSV=$BABASHKA_FEATURE_CSV
@@ -47,6 +49,7 @@ ENV BABASHKA_FEATURE_HSQLDB=$BABASHKA_FEATURE_HSQLDB
 ENV BABASHKA_FEATURE_ORACLEDB=$BABASHKA_FEATURE_ORACLEDB
 ENV BABASHKA_FEATURE_DATASCRIPT=$BABASHKA_FEATURE_DATASCRIPT
 ENV BABASHKA_FEATURE_LANTERNA=$BABASHKA_FEATURE_LANTERNA
+ENV BABASHKA_STATIC=$BABASHKA_STATIC
 
 COPY . .
 RUN ./script/uberjar

script/compile

@@ -76,7 +76,29 @@ args=( "-jar" "$BABASHKA_JAR"
 BABASHKA_STATIC=${BABASHKA_STATIC:-}
 
 if [ "$BABASHKA_STATIC" = "true" ]; then
-    args+=("--static")
+    args+=("--static" "--libc=musl")
+
+    # needs to be in a separate script as we need sudo and >> redirects in it wont work.
+    sudo bash script/setup-musl
+
+    ZLIB_VERSION="1.2.11"
+
+    curl -O -sL "https://zlib.net/zlib-${ZLIB_VERSION}.tar.gz"
+    tar xf "zlib-${ZLIB_VERSION}.tar.gz"
+    cd "zlib-${ZLIB_VERSION}"
+    CC=musl-gcc ./configure --static --prefix=/usr/lib/x86_64-linux-musl/
+    make CC=musl-gcc
+    sudo make install
+    export CC=gcc
+    cd ..
+
+    # depending on GCC version, we will have different directories here.
+    # for example, for GCC 6.3.0 we will have:
+    # - /usr/lib/gcc/x86_64-linux-gnu/6
+    # - /usr/lib/gcc/x86_64-linux-gnu/6.3.0
+    for dest_dir in /usr/lib/gcc/x86_64-linux-gnu/*; do
+        sudo cp -f /usr/lib/x86_64-linux-musl/lib/libz.a "$dest_dir"
+    done
 fi
 
 BABASHKA_FEATURE_HSQLDB=${BABASHKA_FEATURE_HSQLDB:-}

script/setup-musl

@@ -0,0 +1,24 @@
+#!/usr/bin/env bash
+
+# This script sets up the latest available musl-tools using apt pinning from debian unstable.
+# The one available in stable and testing are quite outdated and this ensures we get the latest improvements
+# This explictly installs musl from unstable and keeps the others at a higher priority
+
+cat >> /etc/apt/sources.list <<eof
+deb http://ftp.us.debian.org/debian unstable main non-free contrib
+deb http://non-us.debian.org/debian-non-us unstable/non-us main contrib non-free
+eof
+
+cat >> /etc/apt/preferences <<eof
+Package: *
+Pin: release a=stable
+Pin-Priority: 700
+Package: *
+Pin: release a=testing
+Pin-Priority: 650
+Package: *
+pin: release a=unstable
+pin-priority: 600
+eof
+
+apt-get update -y && apt-get install musl-tools/unstable -y