[gtkmm] minor problem with sorting rows in win32

[bart <gtkmm hakvoort be>]

Hi,

When sorting rows in a treestore i stumbled upon yet another annoying
win32-thingy, it's case-insensitive :`(
When i sort the rows in a linux-environment they'll sort like this:
A
B
a

In an win32 environment it's like this:
A
a
B

Does anyone know how to get around this stupid behaviour?

TIA :-)

Bart