Update rlgl.h

Author: raysan5

src/rlgl.h

@@ -896,7 +896,7 @@ RLAPI void rlLoadDrawQuad(void);     // Load and draw a quad
     // It seems OpenGL ES 2.0 instancing entry points are not defined on Raspberry Pi
     // provided headers (despite being defined in official Khronos GLES2 headers)
     // TODO: Avoid raylib platform-dependent code on rlgl, it should be a completely portable library
-    #if defined(PLATFORM_DRM)
+    #if defined(PLATFORM_DRM)           // Use CONFIG_DRM?
     typedef void (GL_APIENTRYP PFNGLDRAWARRAYSINSTANCEDEXTPROC) (GLenum mode, GLint start, GLsizei count, GLsizei primcount);
     typedef void (GL_APIENTRYP PFNGLDRAWELEMENTSINSTANCEDEXTPROC) (GLenum mode, GLsizei count, GLenum type, const void *indices, GLsizei primcount);
     typedef void (GL_APIENTRYP PFNGLVERTEXATTRIBDIVISOREXTPROC) (GLuint index, GLuint divisor);