Restore macos build on GitHub release-candidate action.

See #7767.

.github/workflows/release-candidate.yml

@@ -81,3 +81,45 @@ jobs:
       with:
         name: windows-release-candidate
         path: windows-release-candidate
+
+  macos:
+
+    runs-on: macOS-10.15
+
+    env:
+        DEVELOPER_DIR: /Applications/Xcode_10.3.app/Contents/Developer
+
+    steps:
+    - uses: actions/checkout@v1
+
+    - name: Build executable
+      run: |
+          stack update
+          stack install
+
+    - name: Create artifacts
+      run: |
+          export VERSION=$(grep '^[Vv]ersion:' pandoc.cabal | awk '{print $$2;}')
+          export ARTIFACTS=macos-release-candidate
+          export RESOURCES=${ARTIFACTS}/Resources
+          export ROOT=${ARTIFACTS}/pandoc
+          export DEST=${ROOT}/usr/local
+          export ME=$(whoami)
+          export BASE=pandoc-$VERSION
+          mkdir -p ${ARTIFACTS}
+          mkdir -p ${RESOURCES}
+          mkdir -p ${DEST}/bin
+          mkdir -p ${DEST}/share/man/man1
+          cp ~/.local/bin/pandoc ${DEST}/bin/
+          strip ${DEST}/bin/pandoc
+          cp man/pandoc.1 ${DEST}/share/man/man1/pandoc.1
+          ~/.local/bin/pandoc -s COPYING.md -Vpagetitle=License -o ${RESOURCES}/license.html
+          chown -R $ME:staff ${ROOT}
+          sed -e "s/PANDOCVERSION/${VERSION}/" macos/distribution.xml.in > ${ARTIFACTS}/distribution.xml
+          cp macos/Makefile ${ARTIFACTS}/
+          echo ${VERSION} > ${ARTIFACTS}/version.txt
+
+    - uses: actions/upload-artifact@v2
+      with:
+        name: macos-release-candidate
+        path: macos-release-candidate