# Macro that checks if variable is defined, otherwise checks env for same name, otherwise uses default value
MACRO(SET_VALUE _variable _default_value)
IF (NOT ${_variable})
IF(DEFINED ENV{${_variable}})
SET(${_variable} $ENV{${_variable}})
ELSE()
SET(${_variable} ${_default_value})
ENDIF()
ENDIF()
ENDMACRO(SET_VALUE)