message: Fix the how-to-build docs
diff: @@ -56,13 +56,13 @@ Run the following commands to configure, build and test core:
  Building for Android required the NDK r10e installed.
  -These targets can be built using the build.sh command:
  +These targets can be built using the cross_compile.sh command:
  - ./build.sh -o android -a armeabi-v7a -t Release -v <X.Y.Z>
  + tools/cross_compile.sh -o android -a armeabi-v7a -t Release -v <X.Y.Z>
  The command shows the available options simply with:
  - ./build.sh
  + tools/cross_compile.sh
  These commands produce a tarball containing the realm static library
  and its include files.
  