In glut 3.7 I can set the video mode using glutInitDisplayString("red=10 green=10 blue=10 alpha=2"); when I query the driver with:
int rbits, gbits, bbits, abits;
I get 10,10,10,2 respectively but using freeglut it will still only give me 8,8,8,8. I haven't tried looking into the code too much myself to figure out why it won't work, but maybe someone who knows the api better can spot the fix sooner.
I'm marking as moderate, because at the moment it means I can't use freeglut, however due to the program I'm writing I require mouse wheel support which glut 3.7 does not provide either and I also use glutLeaveMainLoop