Enable Github Actions to build with Linux and MacOS (#3)

.github/workflows/main.yml

+name: Pt.1 Build with GCC
+# Controls when the action will run. Triggers the workflow on push or pull request
+# events but only for the master branch
+on:
+  push:
+    branches: [ n4.3.1-p1-ci ]
+  pull_request:
+    branches: [ n4.3.1-p1-ci ]
+
+jobs:
+  linux-build_with_docker:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Build FFMpeg
+        shell: bash
+        run: |
+          bash build-with-docker.sh
+      - uses: actions/upload-artifact@master
+        with:
+          name: ffmpeg-linux
+          path: ffmpeg
+  macos-build:
+    runs-on: macos-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Build FFMpeg
+        shell: bash
+        run: |
+          # Make sure to use gcc-8 instead of the default gcc
+          shopt -s expand_aliases
+          alias gcc='gcc-8'
+          bash build.sh
+      - uses: actions/upload-artifact@master
+        with:
+          name: ffmpeg-macos
+          path: ffmpeg
+  # Not working with error messsage:
+  #   C:\ProgramData\Chocolatey\lib\mingw\tools\install\mingw64\x86_64-w64-mingw32\bin\ar.exe: libavfilter/vsink_null: No such file or directory
+  # windows-build:
+  #   runs-on: windows-latest
+  #   steps:
+  #     - uses: actions/checkout@v2
+  #     - name: Build FFMpeg
+  #       shell: bash
+  #       run: |
+  #         bash build.sh

build-with-docker.sh

+#!/bin/bash -x
+
+FLAGS=""
+# Attach TTY only when available, this is for running in Gihub Actions
+if [ -t 1 ]; then FLAGS="-it"; fi
+
+docker pull gcc:8
+docker run $FLAGS \
+  -v $PWD:/usr/src \
+  gcc:8 \
+  sh -c 'cd /usr/src && bash ./build.sh'

build.sh

+#!/bin/bash
+
+./configure --disable-x86asm
+make -j