Sync docs for Android build in INSTALL

docs/gl_ES.UTF-8/INSTALL.txt

@@ -5,7 +5,7 @@
         Copyright © 2002-2023 by varios colaboradores; see AUTHORS.txt.
                              https://tuxpaint.org/
 
-                              23 de Marzo de 2023
+                              29 de Marzo de 2023
 
              +----------------------------------------------------+
              |Índice                                              |
@@ -17,6 +17,7 @@
              |       * Windows                                    |
              |       * Linux/Unix                                 |
              |       * macOS                                      |
+             |       * Android                                    |
              |  * Debugging                                       |
              |  * Uninstalling Tux Paint                          |
              |       * Windows                                    |
@@ -759,7 +760,7 @@ macOS
 
   Building for Apple Silicon
 
-   macOS for Applie Silicon requires all native Apple Silicon applications be
+   macOS for Apple Silicon requires all native Apple Silicon applications be
    signed, even if it is signed "ad-hoc" (anonymously). Because of this,
    compilers that produce native Apple Silicon applications sign all produced
    binaries and libraries as a part of the compilation process.^* However,
@@ -802,6 +803,68 @@ macOS
      $ codesign -s - TuxPaint.app
      $ make TuxPaint.dmg
 
+Android
+
+   29 de Marzo de 2023 Pere Pujal i Carabantes <perepujal@gmail.com> (Edited
+   by Bill Kendrick)
+
+   As of March 2023, the Android build of Tux Paint is maintained in a
+   separate code repository at GitHub:
+   https://github.com/tux4kids/Tuxpaint-Android. Detailed instructions are
+   there; this acts as an overview.
+
+  Prerequisites
+
+   You will need recent versions of:
+     * Gradle — build automation tool
+     * Android Studio (Software Development Kit (SDK)) — to support Android
+       app development (Java)
+     * Android Native Development Kit (NDK) — to support native development
+       in C/C++
+
+   To compile the latest Tux Paint, one has to sync the main SourceForge
+   project's tuxpaint Git repository with the GitHub project's
+   TuxPaint-Android Git repository. (Pere uses a shell script that backs up
+   the app/src/main/jni/tuxpaint directory in the Tuxpaint-Android GitHub
+   repo and makes a build of SourceForge's tuxpaint to generate translations
+   and other things that are not autogenerated in the Android builds, and
+   then copies the SourceForge tuxpaint back to Tuxpaint-Android.) (FIXME: It
+   should be checked-in somewhere. For now, see
+   https://sourceforge.net/p/tuxpaint/feature-requests/224/)
+
+   For it to run you need the tuxpaint and Tuxpaint-Android sources one next
+   to one another, and the script in the directory containing both.
+
+   Fill the app/src/main/assets directory by running cd
+   app/src/main/jni/tuxpaint && ./mkzip_assets.sh
+
+  Building
+
+   The Gradle build generates some variants: Playstore, debugPlaystore,
+   offPlaystore and debugoffPlaystore. You must sign the non-debug ones to be
+   able to install them. (FIXME: Link to info on how to sign.) (Note:
+   "Playstore" ones are intended to be uploaded to Google Play; this is
+   currently managed by Terrence Sheflin —March 2023. "offPlaystore" is the
+   flavor that we distribute as APK files on the Tux Paint website and
+   SourceForge file hosting, and send to the F-Droid app. repository.)
+
+   To trigger a build from F-droid, it suffices to tag a commit and push it
+   to GitHub. That doesn't guarantee the build will succeed though, so Pere
+   usually runs a local F-droid server to test the build and eventually adapt
+   the F-droid's build receipt before pushing the tag to GitHub.
+
+   The builds Pere distributes are all made with that local F-droid server.
+   It has the advantage of packing the sources and logs, and signing the APK.
+   Most importantly, it uses the same tools F-Droid will use to build Tux
+   Paint, so you can detect problems beforehand.
+
+   The receipt Pere uses for F-Droid builds is in the metadata dir of
+   https://gitlab.com/fdroid/fdroiddata. The F-Droid server code is at
+   https://gitlab.com/fdroid/fdroidserver. To generate the server you will
+   need 1GB free on disk. Run the makebuildserver tool they provide, then,
+   from the root of fdroiddata, run ../fdroidserver/fdroid build --server
+   org.tuxpaint:NNNN (NNNN = version, e.g. 9288)
+
                                    Debugging
 
    ⚙ Debugging output — to "STDOUT" on Linux and Unix, to a "stdout.txt" file