Make REGoth compilable with latest bgfx

[Kukunin]

Currently we have 3 bugs with this:

• UI is black, but fully working (you can press enter etc, it just doesn't render)
• Everything is grey-scaled
• There is no bodies

On other hand - it works under MacOS #241

[Kukunin]

After recompilation of shaders with latest bgfx, the latest result is

[Drako]

For whatever reason the PC is missing his right leg xD That is also the case in Gothic 1 btw.

[ataulien]

Found the issue causing the missing legs!

In vs_skinned.sc, put #define BGFX_CONFIG_MAX_BONES 100, before including common.h, so it's like this:

 // ...

#define LOCAL_POSITIONS_1 a_texcoord1
#define LOCAL_POSITIONS_2 a_texcoord2
#define LOCAL_POSITIONS_3 a_texcoord3
#define LOCAL_POSITIONS_4 a_texcoord4
#define BONE_INDICES a_texcoord5
#define WEIGHTS a_texcoord6

#define BGFX_CONFIG_MAX_BONES 100

#include "../common/common.sh"
#include "tools.sh"

uniform vec4 u_color;

// ...

[Kukunin]

Pushed the fix. Hopefully, after CI is done we can merge it

[ataulien]

Works on my machine (tm)