cmake example of optional libraries

example.cmake

find_package(Python)

if(Python_FOUND)
  #if python exists enable plugins that depend on python, this allows the user
  #to turn off the python plugins even if python is found
  option(ENABLE_Python_plugins "Turn on Plugins that depend on python existing" ${Python_FOUND})
endif()


#if you have your python dependent plugins in a directory you can do this
if(ENABLE_Python_plugins)
  add_subdirectory(python_plugins)
endif()

#or if they python plugins are mixed into your source code directories
#you will have to wrap the add_library
if(ENABLE_Python_plugins)
  add_library(python_Lib)
  target_link_library(python_Lib)
endif()

#now if you have lots of places where you are adding libraries that depend on
#python or V8 you might want to create macros that handle all the logic for
#you.

macro (addPythonLibrary name)
if(ENABLE_Python_plugins)
  add_library(${name} ${ARGV})  
endif()
endmacro()

#now to call the macro use:

addPythonLibrary(python_Lib)