Add .travis.yml for macos release candidate build.

We need to build the release candidate on Travis rather
than GitHub actions, because GH has macos 10.15, and
binaries compiled on that OS will not work with 10.13.
See #6622.

This build is only triggered on rc/ branches.

.travis.yml

@@ -0,0 +1,57 @@
+os: osx
+language: generic
+cache:
+  timeout: 1000
+  directories:
+  - "$HOME/.stack/"
+  - ".stack-work/"
+branches:
+  only:
+  - /rc\/.*/
+install:
+- set -e
+- ulimit -n 4096
+- brew install haskell-stack
+- which stack
+- stack --version
+- stack setup
+- stack exec -- ghc --version
+- |
+  export VERSION=$(grep '^[Vv]ersion:' pandoc.cabal | awk '{print $$2;}')
+  export BASEDIR=$(pwd)
+  export ARTIFACTS=${BASEDIR}/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
+  stack build --dependencies-only pandoc pandoc-citeproc
+  stack build pandoc pandoc-citeproc
+  for f in $(find .stack-work/install -name 'pandoc*' -perm +001 -type f); do cp $f ${DEST}/bin/; done
+  strip ${DEST}/bin/pandoc
+  strip ${DEST}/bin/pandoc-citeproc
+  cp man/pandoc.1 ${DEST}/share/man/man1/pandoc.1
+  ${DEST}/bin/pandoc-citeproc --man > \
+    $DEST/share/man/man1/pandoc-citeproc.1
+  ${DEST}/bin/pandoc -t html5 -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
+deploy:
+  on:
+    branch: travis
+  provider: s3
+  bucket: travis-jgm-pandoc
+  region: us-west-1
+  edge: true
+  local_dir: macos-release-candidate
+  access_key_id:
+    secure: ohEst8EP8Z3r/bPMlYgPATo3B/ye48Z0aGp4W1pEhDZjqufLUVTFBIoicvPApCkTrbKMNTdG+KmasrO/leHpju0uFKYQHDtJmHZe3avIOIdbGnOqn97+mmLZBN5skiJWNtrxnN/TuAM+wlePz1dQpohPt6J3S70ct8DsOdZOaGI=
+  secret_access_key:
+    secure: qZ2RN4Bx4WRcVz9H8ae4S6a3AA85kcca0RdMimIREdGSx4ewMYa8lSdcKDvRbPwXRy8H3SeviqL2tTZw3+ej1jccAHowMj8Zvde5EJwX0+qO4Sr0zdWjnsvMeUmx9pO1oL3L/09KTWiMTT+d4XNpE8eqiY08qN8oMj0EPeR/AS4=