Build static Linux binaries with musl (#962)

* Build static Linux binaries with musl

Statically building glibc can be problematic, e.g. it requires the same
(dynamic) glibc version in the system you're running the binary:

    function hsnet_getaddrinfo: warning: Using 'getaddrinfo' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking

This changes the build workflow to build the Linux binaries on a musl environment.

* Add container used for static builds

* Adjust package guards to match after merge

* ci: Fix defaults duplication after merge

* ci: disable haskell setup when using a container

* ci: bump GHC to 9.2.7

* ci: Add README documenting container

* ci: unify cache artifacts

.github/container-linux-static/Dockerfile

@@ -0,0 +1,29 @@
+FROM fpco/alpine-haskell-stack:9.2.7
+
+RUN apk upgrade --no-cache &&\
+    apk add --no-cache \
+        cmake \
+        libtool \
+        openssl-dev \
+        tar \
+        zlib-dev \
+        zlib-static
+
+RUN addgroup \
+        --gid 115 \
+        runneruser \
+    && \
+    adduser \
+        --disabled-password \
+        --gecos "" \
+        --ingroup runneruser \
+        --home /github/home \
+        --uid 1001 \
+        runneruser
+
+RUN mkdir -p /etc/stack &&\
+    { cat /root/.stack/config.yaml ;\
+      echo "system-ghc: true" ;\
+      echo "install-ghc: false" ;\
+      echo "skip-ghc-check: true" ;\
+    } >> /etc/stack/config.yaml

.github/container-linux-static/README.md

@@ -0,0 +1,8 @@
+# Static GHC & musl container
+
+This container is used as part of `.github/workflows/ci.yml` to produce
+statically-linked amd64 linux builds of Echidna. It is based on the following
+container produced by FP Complete and maintained in the
+[`fpco/alpine-haskell-stack`](https://github.com/fpco/alpine-haskell-stack/tree/ghc927)
+repository, and contains a few extra dependencies and configuration to make it
+suitable for the GitHub Actions environment.

.github/workflows/ci.yml

@@ -8,15 +8,21 @@ on:
     branches:
     - master
 
+env:
+  # Tag for cache invalidation
+  CACHE_VERSION: v6
+
 jobs:
   build:
     name: Build Echidna on ${{ matrix.os }}
     runs-on: ${{ matrix.os }}
+    container: ${{ fromJSON(matrix.container || '{"image":null}') }}
     strategy:
       matrix:
         include:
           - os: ubuntu-20.04
             shell: bash
+            container: "{\"image\": \"elopeztob/alpine-haskell-stack-echidna:9.2.7\", \"options\": \"--user 1001\"}"
           - os: macos-latest
             shell: bash
           - os: windows-latest
@@ -55,6 +61,7 @@ jobs:
       - name: Install Stack
         uses: haskell/actions/setup@v2
         id: stack
+        if: matrix.container == ''
         with:
           ghc-version: '9.2'
           enable-stack: true
@@ -69,23 +76,18 @@ jobs:
           path: |
             ~/.local
             D:\a\_temp\msys64\home\runneradmin\.local
-          key: ${{ runner.os }}-local-v5-${{ hashFiles('.github/scripts/install-*') }}
+          key: ${{ runner.os }}-local-${{ env.CACHE_VERSION }}-${{ hashFiles('.github/scripts/install-*') }}
 
-      - name: Cache Stack
+      - name: Cache Stack & Cabal
         uses: actions/cache@v3
         with:
           path: |
             .stack-work
-            ${{ steps.stack.outputs.stack-root }}/*
-            !${{ steps.stack.outputs.stack-root }}/pantry/hackage/*.tar
-            !${{ steps.stack.outputs.stack-root }}/pantry/hackage/*.tar.gz
-          key: ${{ runner.os }}-stack-v5-${{ hashFiles('package.yaml', 'stack.yaml') }}
-
-      - name: Cache Cabal
-        uses: actions/cache@v3
-        with:
-          path: ${{ steps.stack.outputs.cabal-store }}
-          key: ${{ runner.os }}-cabal-v5-${{ hashFiles('package.yaml', 'stack.yaml') }}
+            ${{ steps.stack.outputs.cabal-store || '~/.cabal' }}/*
+            ${{ steps.stack.outputs.stack-root || '~/.stack' }}/*
+            !${{ steps.stack.outputs.stack-root || '~/.stack' }}/pantry/hackage/*.tar
+            !${{ steps.stack.outputs.stack-root || '~/.stack' }}/pantry/hackage/*.tar.gz
+          key: ${{ runner.os }}-stack-${{ env.CACHE_VERSION }}-${{ hashFiles('package.yaml', 'stack.yaml') }}
 
       - name: Build Libraries
         run: |

package.yaml

@@ -79,14 +79,11 @@ executables:
     when:
         - condition: (os(linux) || os(windows)) && flag(static)
           ghc-options:
-            - -static
-            - -O2
-          cc-options: -static
-          ld-options: -static -pthread
-        - condition: os(linux)
+            - -optl-static
+        - condition: os(linux) || os(windows)
           ghc-options:
             - -O2
-          ld-options: -pthread
+            - -optl-pthread
         - condition: os(darwin)
           extra-libraries: c++
           ld-options: -Wl,-keep_dwarf_unwind
@@ -105,14 +102,11 @@ tests:
     when:
         - condition: (os(linux) || os(windows)) && flag(static)
           ghc-options:
-            - -static
-            - -O2
-          cc-options: -static
-          ld-options: -static -pthread
-        - condition: os(linux)
+            - -optl-static
+        - condition: os(linux) || os(windows)
           ghc-options:
             - -O2
-          ld-options: -pthread
+            - -optl-pthread
         - condition: os(darwin)
           extra-libraries: c++
           ld-options: -Wl,-keep_dwarf_unwind