Note this new raygui version embeds ricons and `GuiTextBoxMulti()` is not working properly

* Fix tcc not finding emmintrin.h

This allows to compile raylib with tcc with no errors.

* Remove __TINYC__ check from stb_image.h

This will be placed under textures.c

* Move tcc check to textures.c

Avoiding to change stb_image.h

As far as next raylib version will be 4.0, no backward compatibility hacks will be maintained.

This is a big change for optimization and a more professional understanding of audio. Instead of dealing with samples, now we deal with frames, like miniaudio does, so, avoiding continuous conversions from samples to frames.

Several breaking changes have been done lately so I think it's better to mark raylib for next release as 4.0.

Note that `extern "C"` calling convention only affects objects that need to be seen by the linker, in our case only functions... but it would also be required by global variables exposed, if any.

* GenMeshTangents Fix

* GenMeshTangents Fix - Comment Update

* GenMeshTangents Fix - Comment Update final

* Code Style Changes

* Code Style Changes Final

* Code Style Changes Final 2

* GenMeshTangents better handling for issue #1876

* GenMeshTangents better handling for issue #1876

* GenMeshTangents: Better fix for issue #1876

* vboId location fix

* rlUpdateVertexBuffer - bufferId is an unsigned int

* Fix for issue#1809 - Obj with more materials then mesh caused crash

* Fix for issue#1809 - Formatting Update

- ADDED: rlEnableColorBlend()/rlDisableColorBlend()

* GenMeshTangents Fix

* GenMeshTangents Fix - Comment Update

* GenMeshTangents Fix - Comment Update final

* Code Style Changes

* Code Style Changes Final

* Code Style Changes Final 2

* GenMeshTangents better handling for issue #1876

* GenMeshTangents better handling for issue #1876

* GenMeshTangents: Better fix for issue #1876

* vboId location fix

* rlUpdateVertexBuffer - bufferId is an unsigned int

This commit introduces some breaking changes for library consistency, hopefully not too dramatic... Here the full list:
 - RENAMED: struct `CharInfo` to `GlyphInfo`, actually that's the correct naming for the data contained. It contains the character glyph metrics and the glyph image; in the past it also contained rectangle within the font atlas but that data has been moved to `Font` struct directly, so, `GlyphInfo` is a more correct name.
 - RENAMED: `CodepointToUtf8()` to `CodepointToUTF8()`, capitalization of UTF-8 is the correct form, it would also require de hyphen but it can be omitted in this case.
 - RENAMED: `TextToUtf8()` to `TextCodepointsToUTF8` for consistency and more detail on the functionality.
 - ADDED: `GetGlyphInfo()` to get glyph info for a specific codepoint
 - ADDED: `GetGlyphAtlasRec()` to get glyph rectangle within the generated font atlas
 - Some additional tweaks for consistency

WARNING: DrawTextPro() requires including `rlgl.h`, before it was only dependant on `textures` module.

- DrawTextRec() and DrawTextRecEx() have been moved to example, those functions could be very specific depending on user needs so it's better to give the user the full source in case of special requirements instead of allowing a function with +10 input parameters.

I think it is useful to know what the empty behavior is in cases where
you are enumerating key presses (e.g. implementing "press any key to
continue").

This reverts commit a8e9e1387f.

Now rlgl uses the `Matrix` type, just make sure it has been previously defined somewhere... I don't like this approach but it's probably the easier one for the users... still looking for a better solution... maybe using something like
`#define MATRIX_TYPE`, so it can be checked in other modules.

rlgl has been redesigned to avoid any dependency to `raylib` or `raymath`, all functions using some of those libs have been reviewed.
 - REMOVED: `Texture2D`, `Shader` structs dependency
 - REMOVED: `Vector3`, `Matrix` structs dependency
 - REMOVED: raymath functions dependency, all required math is implemented in rlgl
 - ADDED: `rlMatrix` custom rlgl type
 - ADDED: `utils.c`: `rlMatrixFromMatrix()` and `rlMatrixToMatrix()` for a safe conversion between raylib<->rlgl matrix types
 - ADDED: `rl` prefix to all `rlgl` structs
 - Other small tweaks here and there