Patch to have CMake configure a new header file (ClientDefines.h) with t...

Currently, the downstream clients must set the preprocessor macro ASYNCHRONOUS_CLIENT based on the value that libMOOS was compiled with, or else the generated code headers will differ from the library, and this generally leads to a segmentation fault.

The MOOSConfig.cmake file sets this definition, but it is rather presumptuous that users of libMOOS will always be using CMake and always be compiling from a local source tree.

This patch fixes this problem so that all users (CMake or not, local source tree or /usr/include package directory) can compile with the correct ASYNCHRONOUS_CLIENT settings.