Daniel Verkamp: COMBOOT Support

There seems to be some nasty bug in COM32 loading - playing with menu.c32, I made a menu that could load itself again with menu.c32; this works the first dozen times, but then things blow up - in QEMU, I got a triple fault sometimes (with DEBUG=com32) and other times just a freeze. This happens regardless of the memory size (I tried -m 32 and -m 128 and it breaks at the same number of loads). It seems to actually be crashing outside the com32 loader somewhere, as it hasn't yet called my load or exec function if I am seeing things correctly, so it's probably during the image loading…

Fixed a nasty bug in the “Read file” function: it wasn't returning the number of bytes read correctly, so some things were getting chopped off, and it was interpreting the return value of read_user() incorrectly, so it was reporting the file as completely read before it should have. 2c16f21573cd320c38dff5ff1972767a3422f442