[OE-core] [PATCH V2] mesa: Build separate GLU library

[Ross Burton]

That's a good point well made.

V2, remove the virtual/libglu name and admit that Mesa's GLU is probably the
only GLU that people are going to use, so just package that up as libglu.  If
suddenly people have a burning need to package alternative implementations of
GLU then we can revisit this.

Ross