Fix new 3D engine texture2DLod function missing error on Linux/MESA. MESA requires needed extensions to be explicitly declared in code otherwise it will not enable them.

Src/Graphics/New3D/R3DShaderTriangles.h

@@ -62,6 +62,7 @@ void main(void)
 static const char *fragmentShaderR3D = R"glsl(
 
 #version 120
+#extension GL_ARB_shader_texture_lod : require
 
 uniform sampler2D tex1;			// base tex
 uniform sampler2D tex2;			// micro tex (optional)