Explicity install missing deps GitHub Actions

We seem to have gotten this implicitly before, but now that GitHub has
switched to Ubuntu 24.04 we have to be explicit about it.

.github/workflows/build.yml

@@ -12,6 +12,7 @@ jobs:
         run: |
           sudo apt-get update
           sudo apt-get install -y libfltk1.3-dev fluid gettext appstream
+          sudo apt-get install -y libpixman-1-dev libjpeg-turbo8-dev
           sudo apt-get install -y libgnutls28-dev nettle-dev libgmp-dev
           sudo apt-get install -y libxtst-dev libxdamage-dev libxfixes-dev libxrandr-dev libpam-dev
           sudo apt-get install -y libavcodec-dev libavutil-dev libswscale-dev