do not use SHARE_DATADIR on Android

There is no absolute install path that an app can expect data files on
Android.  Everything is expected to be a path inside of the app, and those
paths depend on the Application ID of the app.  /data/local/tmp is
guaranteed to exist, but will only be usable by the 'shell' and 'root'
users, so this fallback is for debugging only.

This fixes a reproducible issue where the tor-android build harness ended
up including build paths for SHARE_DATADIR.

https://gitlab.torproject.org/tpo/core/tor/-/merge_requests/460

src/app/config/config.c

@@ -483,6 +483,13 @@ static const config_var_t option_vars_[] = {
 #ifdef _WIN32
   V(GeoIPFile,                   FILENAME, "<default>"),
   V(GeoIPv6File,                 FILENAME, "<default>"),
+#elif defined(__ANDROID__)
+  /* Android apps use paths that are configured at runtime.
+   * /data/local/tmp is guaranteed to exist, but will only be
+   * usable by the 'shell' and 'root' users, so this fallback is
+   * for debugging only. */
+  V(GeoIPFile,                   FILENAME, "/data/local/tmp/geoip"),
+  V(GeoIPv6File,                 FILENAME, "/data/local/tmp/geoip6"),
 #else
   V(GeoIPFile,                   FILENAME,
     SHARE_DATADIR PATH_SEPARATOR "tor" PATH_SEPARATOR "geoip"),