D bindgen: add memtrack and fix fetch update

[kassane]

• fix fetch update
• add memtrack

cc: @floooh

Note: Tried add nuklear, spine and gfx_imgui, but get struct error!!

ERROR gen_struct: sspine_t * spine;
ERROR gen_struct: sgimgui_buffer_t * slots;

[floooh]

For some of the headers under util, the hassle to effort to make them bindings compatible probably isn't worth the effort (especially when they depend on 3rd party libs like sokol_spine.h).

[floooh]

...looks like sokol_memtrack.h also has issues (see CI jobs). For sokol_memtrack.h I also wonder if that's all that useful, since it's such a trivial thing to do natively in the target language.

[kassane]

For sokol_memtrack.h I also wonder if that's all that useful, since it's such a trivial thing to do natively in the target language.

In D case, users could use this wrapper to access malloc/free with no interference from GC. Unfortunately, not all users feel comfortable using malloc/free directly.
This avoids creating your own allocation solution.

[floooh]

Oki, is the PR ready, or do you want to do more changes? :)

[kassane]

Done!

[floooh]

...and merged. Thanks!