OS X package build on Travis

This builds an OS X package and deploys it to a GitHub release when a
tag is pushed.  It also generates a tarball reporting the build
environment and configuration.  The build log is still separate.

This is not yet final, it deploys to cgull/mosh and not
mobile-shell/mosh.

It should not affect Linux or OS X CI builds (other than the change to
the Travis Xcode 7.1 image).

Included changes:

The Travis Xcode 7 image seems to have added tmux while we were gone,
breaking our Homebrew setup.

There seems to be no clean reliable way to determine whether a
Homebrew package is installed or needs updating.  Reinstalling is less
efficient but seems to work reliably.

The OS X build is now split between four files:

.travis.yml contains Travis-specific CI/release build configuration.

macosx/brew.sh contains Homebrew-specific package manager installs and
reporting.

macosx/osx-xcode.sh contains Apple-specific OS/X and Xcode reporting.

macosx/build.sh does the actual package build.

.travis.yml

@@ -1,5 +1,5 @@
-osx_image: xcode8
-
+# This does Travis CI builds on Linux and OS X, and on a tag build,
+# also produces an OS X package.
 os:
   - linux
   - osx
@@ -8,28 +8,95 @@ cache:
   - apt
 
 language: cpp
+
+# Use the Ubuntu 14.04 build environment for Linux.
 sudo: required
 dist: trusty
 
+# Currently we're using the Travis Xcode 7.1/OS X 10.10 image to
+# get i386/x86_64 fat binaries.
+osx_image: xcode7.1
+
+# Linux dependencies
 addons:
   apt:
     packages:
+    # For build.
     - protobuf-compiler
     - libprotobuf-dev
     - libutempter-dev
-    - tmux			# test suite
-    - perl			# test suite
+    # Test suite needs these.
+    - tmux
+    - perl
 
 before_install:
-  - if test "$TRAVIS_OS_NAME" = osx; then brew update; fi
-  - if test "$TRAVIS_OS_NAME" = osx; then brew install protobuf tmux; fi
-  - if test "$TRAVIS_OS_NAME" = osx; then brew outdated protobuf tmux || brew upgrade protobuf tmux; fi
+  # Get full repo for `git describe`
   - git fetch --tags --unshallow
+  # OS X dependencies.  The package_deps step takes 15 minutes or so
+  # and is fairly quiet, so wrap it in travis_wait to keep it from
+  # being killed.
+  - |
+    (
+      set -e
+      if test osx = "${TRAVIS_OS_NAME}"; then
+        macosx/brew-deps.sh install
+        if test -n "${TRAVIS_TAG}"; then
+          travis_wait 30 macosx/brew-deps.sh package_deps
+        else
+          macosx/brew-deps.sh deps
+        fi
+      fi
+    )
 
+# Use before_script to report the build configuration.
+before_script:
+  # Describe this system.
+  - id
+  - env
+  - git describe --long
+  - |
+    (
+      set -e
+      if test osx = "${TRAVIS_OS_NAME}" && test -n "${TRAVIS_TAG}"; then
+        rm -rf macosx/build-report "macosx/${TRAVIS_TAG}-build-report.tbz"
+        mkdir macosx/build-report
+        cd macosx/build-report
+        ../brew-deps.sh describe
+        ../osx-xcode.sh describe
+        tar -cjf "../${TRAVIS_TAG}-build-report.tbz" .
+      fi
+    )
+
+# 'make distcheck', and OS X package build on tag builds.
 script:
   - ./autogen.sh
   - ./configure --enable-compile-warnings=error --enable-examples
   - make distcheck VERBOSE=1 V=1
+  # Build OS X package for tags.
+  - |
+    if test osx = "${TRAVIS_OS_NAME}" && test -n "${TRAVIS_TAG}"; then
+      (
+        set -e
+        cd macosx
+        env MACOSX_DEPLOYMENT_TARGET=10.10 ./build.sh
+        shasum -a 256 "${TRAVIS_TAG}.pkg" "${TRAVIS_TAG}-build-report.tbz"
+      )
+    fi
+# Deploy the OS X package to a GitHub release.
+deploy:
+  provider: releases
+  api_key:
+    secure: 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
+  # Save build artifacts.
+  skip_cleanup: true
+  # Using a shell variable in deploy.file is undocumented but seems to work.
+  file:
+    - macosx/${TRAVIS_TAG}.pkg
+    - macosx/${TRAVIS_TAG}-build-report.tbz
+  on:
+    repo: cgull/mosh
+    tags: true
+    condition: ${TRAVIS_OS_NAME} = osx
 
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