travis: update macOS images and make building faster

don't build our own ffmpeg anymore and instead use the bottled version
from homebrew. update the newest macOS image. also handle macOS 10.12
as a legacy OS since homebrew and Apple stopped supporting it.
nevertheless it's helpful to build on that version since it's the last
version we support building on. it's a bit special since we have to pin
the homebrew-core version to a previous one where all the bottles for
macOS 10.12 are still available, otherwise it would build nearly
everything from source and that would take ages. also start caching the
homebrew cache folder for downloads.

.travis.yml

@@ -1,16 +1,29 @@
 language: c
 
+macbase:
+  - &macOld
+    os: osx
+    compiler: clang
+    env:
+      - HOMEBREW_NO_AUTO_UPDATE=1
+      - HOMEBREW_NO_INSTALL_CLEANUP=1
+  - &macNew
+    <<: *macOld
+    addons:
+      homebrew:
+        packages: ['autoconf', 'automake', 'ffmpeg', 'freetype', 'fribidi',
+                   'libass', 'libtool', 'little-cms2', 'luajit', 'nasm',
+                   'pkg-config', 'python']
+        update: true
+
 matrix:
   include:
-    - os: osx
-      osx_image: xcode11
-      compiler: clang
-    - os: osx
+    - <<: *macNew
+      osx_image: xcode11.3
+    - <<: *macNew
       osx_image: xcode10.1
-      compiler: clang
-    - os: osx
+    - <<: *macOld
       osx_image: xcode9.2
-      compiler: clang
     - os: linux
       compiler: gcc
       env: CONTAINER=registry.cirno.systems/kiwi/containers/mpv-ci:stable-deps CI_SCRIPT=ci/build-tumbleweed.sh
@@ -21,6 +34,10 @@ matrix:
       env: CONTAINER=registry.cirno.systems/kiwi/containers/mpv-ci-mingw64:i686 CI_SCRIPT=ci/build-mingw64.sh TARGET=i686-w64-mingw32
     - os: linux
       env: CONTAINER=registry.cirno.systems/kiwi/containers/mpv-ci-mingw64:x86_64 CI_SCRIPT=ci/build-mingw64.sh TARGET=x86_64-w64-mingw32
+  allow_failures:
+    - os: osx
+      osx_image: xcode9.2
+  fast_finish: true
 
 dist: bionic
 services:
@@ -48,9 +65,34 @@ before_install:
   - if [ "$TRAVIS_OS_NAME" = "linux" ]; then docker pull $CONTAINER; fi
   - |
         if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then
-            brew link --overwrite python
-            "$TRAVIS_BUILD_DIR/ci/get_ffmpeg.sh"
+            if [[ "$TRAVIS_OSX_IMAGE" == "xcode9.2" ]]; then
+                brew update
+                pushd "/usr/local/Homebrew/Library/Taps/homebrew/homebrew-core"
+                git checkout 55e02323812604add9a69bab8730319b9255a697
+                popd
+                brew install autoconf
+                brew install automake
+                brew install pkg-config
+                brew install libtool
+                brew install python
+                brew install freetype
+                brew install fribidi
+                brew install little-cms2
+                brew install luajit
+                brew install libass
+                brew install ffmpeg
+            else
+                brew link --overwrite python
+            fi
         fi
+
+before_cache:
+  - if [ "$TRAVIS_OS_NAME" = "osx" ]; then brew cleanup -s ; fi
+
+cache:
+  directories:
+    - $HOME/Library/Caches/Homebrew
+
 script:
   - ./bootstrap.py
   - if [ "$TRAVIS_OS_NAME" = "linux" ]; then docker run --env CC --env TARGET -v $TRAVIS_BUILD_DIR:/build $CONTAINER /bin/sh -c "cd /build && $CI_SCRIPT"; fi
@@ -75,17 +117,3 @@ addons:
     build_command_prepend: "./bootstrap.py && ./waf configure"
     build_command:   "./waf build"
     branch_pattern: coverity_scan
-  homebrew:
-    packages:
-      - autoconf
-      - automake
-      - freetype
-      - fribidi
-      - libass
-      - libtool
-      - little-cms2
-      - luajit
-      - nasm
-      - pkg-config
-      - python
-    update: true

ci/get_ffmpeg.sh

@@ -1,38 +0,0 @@
-#!/usr/bin/env bash
-
-set -e
-
-FFMPEG_SRC_DIR="${HOME}/deps/src/ffmpeg"
-FFMPEG_BUILD_DIR="${FFMPEG_SRC_DIR}/${TRAVIS_OS_NAME}"
-FFMPEG_SYSROOT="${HOME}/deps/sysroot"
-FFMPEG_HASH="18928e2bb4568cbe5e9061c3e6b63559392af3d2"
-
-# Get the sauce if not around
-if [[ ! -d "${FFMPEG_SRC_DIR}" ]] ; then
-    git clone "https://git.videolan.org/git/ffmpeg.git" "${FFMPEG_SRC_DIR}"
-fi
-
-# pop into FFmpeg's source dir and clean up & check out our wanted revision
-pushd "${FFMPEG_SRC_DIR}"
-git reset --hard HEAD && git clean -dfx
-git checkout "${FFMPEG_HASH}"
-popd
-
-# If a build dir of the same type is around, clean it up
-if [[ -d "${FFMPEG_BUILD_DIR}" ]] ; then
-    rm -rf "${FFMPEG_BUILD_DIR}"
-fi
-
-# Create and move into the build dir, configure and build!
-mkdir -p "${FFMPEG_BUILD_DIR}" && pushd "${FFMPEG_BUILD_DIR}"
-
-PKG_CONFIG_PATH="${FFMPEG_SYSROOT}/lib/pkgconfig/" ../configure \
-  --disable-{autodetect,stripping} \
-  --cc="${CC}" \
-  --cxx="${CXX}" \
-  --prefix="${FFMPEG_SYSROOT}" \
-  --enable-{zlib,securetransport,videotoolbox}
-
-make -j4 && make install && popd
-
-exit 0