Add top level build script for building packages.

README.rst

 naclports - Ports of open source software to Native Client
 ==========================================================
 
 naclports is collection of open source libraries and applications that have
 been ported to Native Client, along with set to tools for building and maintain
 them.
 
 The ports themselves live in the ``ports`` directory.  Each one contains a
 description of the package (pkg_info), a bash script for building it (build.sh)
-and an optional patch file (nacl.patch).  The build script will download,
-patch, build and install the application or library.
+and an optional patch file (nacl.patch).  To build a package run the
+naclports.sh script from the package directory.  The build script will
+download, patch, build and install the application or library.
 
-The scripts require that certain tools are present in the host system.
+The build scripts require that certain tools are present in the host system.
 You will need at least these (but probably more):
 
 - bash
 - make
 - sed
 - git
 - autoconf, automake
 - pkg-config
 - gettext
-- libglib2.0-dev >= 2.26.0 (if you want to build nacl-glib)
+- libglib2.0-dev >= 2.26.0 (if you want to build glib)
 
 Before you can build any of the package you must set the NACL_SDK_ROOT
 environment variable to top directory of a version of the Native Client SDK
 (the directory containing toolchain/).  This path should be absolute.
 
 The top level Makefile can be used to build one of more of the packages.
 Package dependencies are built into this Makefile. For example, ``make vorbis``
 will build ``libvorbis-1.2.3`` and ``libogg-1.1.4``.  ``make all`` will build
-all of the ports.
+all of the packages.
 
 There are 4 possible architectures that NaCl modules can be compiled for: i686,
 x86_64, arm, pnacl.  The naclports build system will build just one at at time.
 You can control which one by setting the ``NACL_ARCH`` environment variable.
 E.g.::
 
   $ NACL_ARCH=arm make openssl
 
 If you want to build a certain package for all architectures you can use the
 top level ``make_all.sh`` script.  E.g.::
@@ skipping 30 matching lines @@
 Adding a new package
 --------------------
 
 To add a package:
 
 1. If you are using svn, make sure you have a writable version of the
    repository::
 
      $ gclient config https://naclports.googlecode.com/svn/trunk/src
 
-2. Add a directory to the ``ports`` directory using the name your new port.
+2. Add a directory to the ``ports`` directory using the name your new package.
    For example: ``ports/openssl``.
 3. Add the build.sh script and pkg_info to that directory.
 4. Optionally include the upstream tarball and create a .sha1 checksum file.
    You can do this using ``build_tools/sha1sum.py``.  Redirect the script
    output to a .sha1 file so that the build system will find it.  E.g.::
 
      $ sha1sum.py mypkg.tar.gz > ports/openssl/openssl-0.0.1.sha1
 
 5. Optionally include a patch file (nacl.patch).  See below for the
    recommended way to generate this patch.
-6. Add the invocation of your script, and any dependencies to the top level
-   Makefile.
+6. Add the new package, and any dependencies to the top level Makefile.
 7. Make sure your package builds for all architectures::
 
      $ ./make_all.sh <PACKAGE_NAME>
 
 Modifying package sources / Working with patches
 ------------------------------------------------
 
 When a package is first built, its source is downloaded and extracted to
 ``out/repository/<PKG_NAME>``.  A new git repository is then created in this
 folder with the original archive contents on a branch called ``upstream``.  The
 optional ``nacl.patch`` file is then applied on the ``master`` branch.  This
 means that at any given time you can see the changes from upstream using ``git
 diff upstream``.
 
 To make changes to a package's patch file the recommended workflow is:
 
 1. Directly modify the sources in ``out/repository/PKG_NAME``.
 2. Build the package and verify the changes.
 3. Use ``git diff upstream.. > ../path/to/nacl.patch`` to regenerate
    the patch file.
 
 Whenever the upstream archive or patch file changes and you try to build the
 package you will be prompted to remove the existing repository and start a new
 one. This is to avoid deleting a repository that might have unsaved changed.