Update gen_stubs.php to generate C enums from internal enums, when the stub is annotated with @generate-c-enums. Enum values can be compared to the result of zend_enum_fetch_case_id(zend_object*).
The generated enums are added to separate files named {$extensionName}_decl.h, so that it's possible to include these from anywhere. _arginfo.h files would generate warnings if we tried to include them in a compilation unit that doesn't call the register_{$class} functions, for instance.
Introduce Z_PARAM_ENUM().
* Make ZEND_AST_CONST_ENUM_INIT a 4-children node
* Store enum case id in ZEND_AST_CONST_ENUM_INIT
* Store enum case id in instance
* Expose enum case_id internally
* Generate C enum for internal enums
* Introduce Z_PARAM_ENUM()
* Port extensions
