To build the optional Avalon Toolkit support, run cmake with the
-DRDK_BUILD_AVALON_SUPPORT=ON argument. If the Avalon Toolkit sources
could not be found, the CMake build system will attempt to download the
Avalon Toolkit distribution from the following URL:

http://sourceforge.net/projects/avalontoolkit/files/AvalonToolkit_1.2/AvalonToolkit_1.2.0.source.tar

The downloaded Avalon Toolkit sources will be automatically patched to
avoid a potential memory corruption issue.
The default download URL and MD5 checksum can be overridden with the
following CMake definitions:

AVALONTOOLS_URL
AVALONTOOLS_MD5SUM

If AVALONTOOLS_URL is set to "", no download will be attempted.
If AVALONTOOLS_MD5SUM is set to "", no MD5 checksum will be performed.

If you prefer to install Avalon Toolkit sources manually, please download
a copy of the source from:
http://sourceforge.net/projects/avalontoolkit/files/AvalonToolkit_1.2/AvalonToolkit_1.2.0.source.tar

Note that the version number is important.

Extract the tar file in $RDBASE/External/AvalonTools; the source required by the RDKit is in
the SourceDistribution directory.

cd to $RDBASE/External/AvalonTools and apply AvalonToolkit_1.2_patch.txt:

$ patch -p0 < AvalonToolkit_1.2_patch.txt
