December 24
The docs states

Consequences
As no Druntime is available, many D features won't work. For example:

    Garbage Collection
    Thread-local storage
    TypeInfo and ModuleInfo
    Classes
    Built-in threading (e.g. core.thread)
    Dynamic arrays (but not slices) and associative arrays
    Exceptions
    switch with strings
    final switch
    synchronized and core.sync
    Static module constructors or deconstructors
    Struct deconstructors
    unittest (testing can be as usual with the -betterC flag)

The predefined version D_BetterC can be used for conditional compilation.

Are each of these still valid statements?

Also, is the GC os independent? I see there is an os module for the gc, but does it require the os for any particular reason?
December 24
On 24/12/2017 10:02 AM, Amorphorious wrote:
> The docs states
> 
> Consequences
> As no Druntime is available, many D features won't work. For example:
> 
>      Garbage Collection
>      Thread-local storage
>      TypeInfo and ModuleInfo
>      Classes
>      Built-in threading (e.g. core.thread)
>      Dynamic arrays (but not slices) and associative arrays
>      Exceptions
>      switch with strings
>      final switch
>      synchronized and core.sync
>      Static module constructors or deconstructors
>      Struct deconstructors
>      unittest (testing can be as usual with the -betterC flag)
> 
> The predefined version D_BetterC can be used for conditional compilation.
> 
> Are each of these still valid statements?
> 
> Also, is the GC os independent? I see there is an os module for the gc, but does it require the os for any particular reason?

It requires druntime for threading and TLS support. Which are both tied to the compiler and OS.