/DEFINE
       /DEFINE=(identifier[=definition][,...])
       /NODEFINE (D)

    Performs the same function as the #define preprocessor
    directive. That is, /DEFINE defines a token string or macro to
    be substituted for every occurrence of a given identifier in the
    program.

    DCL converts all input to uppercase unless it is enclosed in
    quotation marks.

    The simplest form of a /DEFINE definition is as follows:

     /DEFINE=true

    This results in a definition like the one that would result from
    the following definition:

     #define TRUE 1

    When more than one /DEFINE is present on the CXX command line or
    in a single compilation unit, only the last /DEFINE is used.

    When both /DEFINE and /UNDEFINE are present on a command line,
    /DEFINE is evaluated before /UNDEFINE.