The following symbols are predefined in the IDC preprocessor:
_NT_ IDA is running under MS Windows
_LINUX_ IDA is running under Linux
_MAC_ IDA is running under Mac OS X
_UNIX_ IDA is running under Unix (linux or mac)
_EA64_ 64-bit version IDA
_QT_ GUI version of IDA (Qt)
_GUI GUI version of IDA
_TXT_ Text version of IDA
_IDA_VERSION_ The current IDA version. For example: "8.4"
_IDAVER_ The current, numerical IDA version. For example: "840" means v8.4
These symbols are also defined when parsing C header files.