I forget right now how to get the handle of a GLUT window (if indeed GLUT includes a method to do this), though typically the following code will perform this task:
long dwStyle = GetWindowLong(hwnd, GWL_STYLE);
dwStyle ^= WS_MAXIMIZEBOX;
SetWindowLong(hwnd, GWL_STYLE, dwStyle);
1. Get the current window style
2. Toggle the maximize-box bit
3. Send the new style back to the window
You'll just have to either (a) get GLUT to give you a handle for this window, or (2) use the standard windows functions for getting a handle to this window - should be reasonably trivial, since you've created the window and know what it's window text(title) is.
EDIT: Nope, GLUT no includes a function to retrieve a HWND of the main window, you'll have to do this yourself. Please find below a function that will do the lot for you.
Function
void toggleGlutWindowMaximizeBox(char *szWindowTitle)
{
long dwStyle;
HWND hwndGlut;
hwndGlut = FindWindow(NULL, szWindowTitle);
dwStyle = GetWindowLong(hwndGlut, GWL_STYLE);
dwStyle ^= WS_MAXIMIZEBOX;
SetWindowLong(hwndGlut, GWL_STYLE, dwStyle);
}
Example of Use
char *szWindowTitle = "GLUT Shapes";
....
....
....
glutCreateWindow(szWindowTitle);
toggleGlutWindowMaximizeBox(szWindowTitle);