doc/Build.md: add build information for alpine

doc/Build.md

@@ -9,6 +9,44 @@ sudo apt install libasound2-dev libavcodec-dev libcap-dev  libdrm-dev libglib2.0
 sudo dnf install java-17-openjdk-devel 'pkgconfig(gtk4)' 'pkgconfig(libbsd)' 'pkgconfig(libportal)' 'pkgconfig(sqlite3)' 'pkgconfig(libwebp)' 'pkgconfig(liblz4)' 'pkgconfig(openxr)'
 ```
 
+### Alpine Edge
+
+Alpine has ATL already packaged in their testing repository. This means that if you are running Alpine edge --- either as your host OS or in a container --- you can install ATL or its development dependencies through `apk`.
+
+If you are not using Alpine edge, you can get a containerized setup running using toolbox:
+
+```sh
+toolbox create --image quay.io/toolbx-images/alpine-toolbox:edge atl_dev
+toolbox enter atl_dev
+```
+
+In both case you will need to add the testing repository to your apk configuration:
+
+```sh
+echo "https://dl-cdn.alpinelinux.org/alpine/edge/testing" | sudo tee -a /etc/apk/repositories
+```
+
+#### Installing the ATL package
+
+With this setup installing ATL becomes trivial:
+
+```sh
+sudo apk add android-translation-layer
+```
+
+#### Installing ATL from source
+
+If you want to build ATL from source, you can take advantage of the packages for its dependencies. With this you can skip the Additional Dependency section below.
+
+```sh
+sudo apk add build-base meson java-common openjdk8-jdk \
+    pc:alsa pc:glib-2.0 pc:gtk4 pc:gudev-1.0 pc:libportal \
+    pc:openxr pc:vulkan pc:webkitgtk-6.0 ffmpeg-dev \
+    bionic_translation-dev art_standalone-dev skia-sharp-dev
+```
+
+You can now skip the Additional Dependencies section and continue with the build steps from below.
+
 ## Additional Dependencies
 ### Skia
 If you distro ships this already (e.g. `skia-sharp` on Alpine), you can just install the package and skip this step.