OpenGL.arrays._strings
Run-time calculation of offset into Python string structure
Does a scan to find the digits of pi in a string structure
in order to produce an offset that can be used to produce
data-pointers from Python strings.
Porting note:
Currently this uses id( str a ) to get the base address
of the Python string. Python implementations where id( a )
is *not* the memory address of the string will not work!