To compile ConnectBot using Ant, you must specify where your Android SDK is via the local.properties file. Insert a line similar to the following with the full path to your SDK:
sdk.dir=/usr/local/android
Download the ProGuard distribution from its website at http://proguard.sourceforge.net/ and place the proguard.jar into the "tools" subdirectory in the ConnectBot root directory.
When running ant to build ConnectBot and engage ProGuard, use:
ant proguard release