'ndk-build' Overview

I. Usage:
---------

The Android NDK r4 introduced a new tiny shell script, named 'ndk-build',
to simplify building machine code.

The script is located at the top-level directory of the NDK, and shall
be invoked from the command-line when in your application project
directory, or any of its sub-directories. For example:

    cd $PROJECT
    $NDK/ndk-build

Where $NDK points to your NDK installation path. You can also create an
alias or add $NDK to your PATH to avoid typing it everytime.


II. Options:
------------

All parameters to 'ndk-build' are passed directly to the underlying GNU Make
command that runs the NDK build scripts. Notable uses include:

  ndk-build                  --> rebuild required machine code.
  ndk-build clean            --> clean all generated binaries.

  ndk-build V=1              --> launch build, displaying build commands.

  ndk-build -B               --> force a complete rebuild.

  ndk-build -B V=1           --> force a complete rebuild and display build
                                 commands.

  ndk-build NDK_LOG=1        --> display internal NDK log messages
                                 (used for debugging the NDK itself).

  ndk-build NDK_APP_APPLICATION_MK=<file>
    --> rebuild, using a specific Application.mk pointed to by
        the NDK_APP_APPLICATION_MK command-line variable.

  ndk-build -C <project>     --> build the native code for the project
                                 path located at <project>. Useful if you
                                 don't want to 'cd' to it in your terminal.


III. Requirements:
------------------

You need GNU Make 3.81 or later to use 'ndk-build' or the NDK in general.
The build scripts will detect that you're using a non-compliant Make tool
and will complain with an error message.

If you have GNU Make 3.81 installed, but that it is not launched by the
default 'make' command, define GNUMAKE in your environment to point to it
before launching 'ndk-build'. For example:

    GNUMAKE=/usr/local/bin/gmake ndk-build

Or to make the change more permanent:

    export GNUMAKE=/usr/local/bin/gmake
    ndk-build

Adapt to your shell and GNU Make 3.81 installation location.


III. Internals:
---------------

'ndk-build' itself is a tiny wrapper around GNU Make, its purpose is simply
to invoke the right NDK build script, it is equivalent to;

    $GNUMAKE -f $NDK/build/core/build-local.mk [parameters]

Where '$GNUMAKE' points to GNU Make 3.81 or later, and $NDK points to your
NDK installation directory.

Use this knowledge if you want to invoke the NDK build script from other
shell scripts (or even your own Makefiles).
