Blocks Runtime library

 Blocks are a proposed extension to the C, Objective C, and C++ languages
 developed by Apple to support the Grand Central Dispatch concurrency engine.
 Blocks are anonymous inline functions that automatically capture a read-only
 copy of local variables, and have read-write access to local variables that
 are declared with the "__block" storage class.
 .
 This package contains a library that is needed by programs that use Blocks.