Update: Major changes regarding file functions.

Update: Major changes regarding file functions.

I like having support for "standard" debug and "standard" warning.
The problem is that there is no such standard.
These are made available in case there ever is.
I want to simplify the code, so get rid of this non-standard "standard" code.

The low-level file functions inconsistently used id, stream, and file structure.
Switch everything to use the file structure.

Relax function errors by having invalid stream or invalid file descriptor return without error bit set.
In these cases use special status codes F_stream_not and F_file_descriptor_not as appropriate.

Simplify the functions to be simpler.
Some of the functions, namely the close functions, also support conditionally flushing before close.
Remove the flushing and the passed boolean.
Let the caller use two functions directly rather than building this in.

Add missing function for flushing via the file descriptor.

The private_f_file_flush() function is missing several disable macro checks.
(This change needs to be backported.)

This change does not address the tests.
This change does not address the programs that use or might use the changed, new, or deleted code.