Revert "(#4) temporarily run test-third-party-build on system's ffmpeg"

This reverts commit 769494543e745ab909c77fee123734a6b7a461e5.

Forgot that their ffmpeg is too old to even make my code compile ( ._.)

.github/workflows/ci.yml

@@ -10,7 +10,7 @@ jobs:
       - name: install dependencies
         run: |
           sudo apt-get update
-          sudo apt-get install -qq nasm libfreetype6-dev libgif-dev libavutil-dev libavcodec-dev libcurl4-openssl-dev
+          sudo apt-get install -qq nasm libfreetype6-dev libgif-dev libcurl4-openssl-dev
       - uses: actions/cache@v1
         with:
           # TODO: centralize ffmpeg version in the build

Makefile

@@ -1,6 +1,6 @@
-VODUS_PKGS=freetype2 libavcodec libavutil
-VODUS_CXXFLAGS=-Wall -fno-exceptions -std=c++17 -ggdb `pkg-config --cflags $(VODUS_PKGS)`
-VODUS_LIBS=`pkg-config --libs $(VODUS_PKGS)` -lgif
+VODUS_PKGS=freetype2
+VODUS_CXXFLAGS=-Wall -fno-exceptions -std=c++17 -ggdb `pkg-config --cflags $(VODUS_PKGS)` -I./third_party/ffmpeg-4.3-dist/usr/local/include/
+VODUS_LIBS=`pkg-config --libs $(VODUS_PKGS)` -lgif -L./third_party/ffmpeg-4.3-dist/usr/local/lib/ -lavcodec -lavutil -lswresample -pthread -lm -llzma -lz
 
 EMOTE_DOWNLOADER_PKGS=libcurl
 EMOTE_DOWNLOADER_CXXFLAGS=-Wall -fno-exceptions -std=c++17 -ggdb `pkg-config --cflags $(EMOTE_DOWNLOADER_PKGS)`