[Bug preprocessor/71851] Get more time granularity at preprocessing

[daniel.gutson at intel dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71851

--- Comment #5 from Daniel Gutson <daniel.gutson at intel dot com> ---
The idea is that the macro expands always to the same value.
The final usage of this facility should not be of any matter to gcc, it will be
just another program.
This macro would change break reproduceability as much as __TIME__ does.
IOW, just another predefined macro that will be used in the program.
Anecdotically it will be used for randomization seeding.
Richard, what would __RANDOM__ expand to? Please see that I try to maintain
separated the use case from the functionality, a functionality that is already
present (getting time during preprocessing but with more precision).