CheckLibraryExists

Check if the function exists.

CHECK_LIBRARY_EXISTS (LIBRARY FUNCTION LOCATION VARIABLE)

LIBRARY  - the name of the library you are looking for
FUNCTION - the name of the function
LOCATION - location where the library should be found
VARIABLE - variable to store the result

The following variables may be set before calling this macro to modify the way the check is run:

CMAKE_REQUIRED_FLAGS = string of compile command line flags
CMAKE_REQUIRED_DEFINITIONS = list of macros to define (-DFOO=bar)
CMAKE_REQUIRED_LIBRARIES = list of libraries to link