function. MSDN suggests using gluErrorUnicodeStringWIN
instead of gluErrorString, as it allows both ANSI and Unicode
error strings.
* include/GL/glu.h (gluErrorUnicodeStringEXT): Make the
returned pointer const for consistency reasons.
headers from OpenGL Sample Implementation. Windows ships with
GLU 1.2 so some constants and functions were removed. Then some
typedef's and function declarations were reworked to look like
the previous GL/glu.h.
