Updated nuklear to work on GNU compiler.

[aperfilev]

On GNU GDC compiler impossible to compile nuklear extension due to small problem:

While for DMD & LDC2 this is not an issue but in GDC
Variadic static array args cannot be passed to extern(C) method as value. Need to be converted into a pointer.

~/dagon/extensions/nuklear$ dub build --compiler=gdc
    Starting Performing "debug" build using gdc for x86_64.
    Building nuklear ~master: building configuration [library]
src/dagon/ext/nuklear.d:1096:56: error: cannot pass static arrays to ‘extern(C)’ vararg functions
 1096 |         nk_labelf_colored(&ctx, align_, color, format, args);
      |                                                        ^
src/dagon/ext/nuklear.d:1103:38: error: cannot pass static arrays to ‘extern(C)’ vararg functions
 1103 |         nk_labelf_wrap(&ctx, format, args);
      |                                      ^
src/dagon/ext/nuklear.d:1110:53: error: cannot pass static arrays to ‘extern(C)’ vararg functions
 1110 |         nk_labelf_colored_wrap(&ctx, color, format, args);
      |                                                     ^
Error gdc failed with exit code 1.

[aperfilev]

I think pipeline failed due to network issue within pipeline

[aperfilev]

@gecko0307 Please check these pipelines - they seems not updating dmd version correct.