Since we switched from autotools to Meson in commit
94592c14, we don't need to include
`config.h` early to properly enable large file support.  Meson passes
the required macros on the compiler command line instead of defining
them in `config.h`.

This means we can include `config.h` at any time, whenever we want to
check its macros, and there are no ordering constraints.

Avoid GLib.

Prepare for adding state.

Replaces GLib's GError.

Some compilers are very picky, but we really aren't interested in the
return value.

Some compilers are very picky, but we really aren't interested in the
return value.

The other audio_format attributes are not used.

Declaring the global variable _CRT_fmode is a documented hack.  What
an ugly platform!

This patch prepares support for floating point samples (and probably
other formats).  It changes the meaning of the "bits" attribute from a
bit count to a symbolic value.

Assign default value only if none was given on the command line.

After we've been hit by Large File Support problems several times in
the past week (which only occur on 32 bit platforms, which I don't
have), this is yet another attempt to fix the issue.

An asterisk means that this attribute should not be enforced, and
stays whatever it used to be.  This way, some configuration values
work like masks.

It makes no difference right now, but we're about to add an endianness
flag and will want to make sure it's correctly initialised every time.