Use GCC instead of TCC, since TCC doesn't support linker scripts that well.
GDT and IDT and ISRS - code mostly copied verbatim from:
James Malloy. http://www.jamesmolloy.co.uk/tutorial_html/4.-The%20GDT%20and%20IDT.html
Brandon Friesen. http://www.osdever.net/bkerndev/Docs/gdt.htm

also, start a clib with a memset implementation.
implement GDT and IDT fully
Remove a few GCC compiler warnings
LetkuOS is now MIT licensed