In general, an implementation is free to ignore
declaration specifiers except for the
declaration
,
notinline
,
safety
,
and special
declaration specifiers.
A declaration declaration must suppress warnings
about unrecognized declarations of the kind that it declares.
If an implementation does not produce warnings about
unrecognized declarations, it may safely ignore this declaration.
A notinline declaration must be recognized by any implementation
that supports inline functions or compiler macros in order to disable those facilities.
An implementation that does not use inline functions or compiler macros
may safely ignore this declaration.
A safety declaration that increases the current safety level
must always be recognized. An implementation that always processes
code as if safety were high may safely ignore this declaration.
A special declaration must be processed by all implementations.