5.20 define option (-D)

This is the "name to add to definition list" option.

This option has some usage constraints. It:

• may appear an unlimited number of times.
• is a member of the define class of options.

The AutoGen define names are used for the following purposes:

1. Sections of the AutoGen definitions may be enabled or disabled by using C-style #ifdef and #ifndef directives.
2. When defining a value for a name, you may specify the index for a particular value. That index may be a literal value, a define option or a value #define-d in the definitions themselves.
3. The name of a file may be prefixed with $NAME. That part of the name string will be replaced with the define-d value for NAME.
4. While processing a template, you may specify an index to retrieve a specific value. That index may also be a define-d value.