glActiveTextureARB and old headers

I have a problem. I want to use multitexturing,
but my compiler (borland c++ builder 6.0) doesn’t…
I try to include <gl\glext.h>, but compiler doesn’t even
look into it - displays ‘call to undefined function’
Can anyone help me? If that matters I’m using GLFW
as a framework.

I believe you need to load the function, not just define it. Take a look at in the tut section. They have a multitexturing tut