str.c: fix a compile warning about LONG_MIN not fitting in int variable
strklos.h: made EXTERN_PRIMITIVE actually declare the primitive extern, and
 also declare its associated primitive_obj as extern.
vm.c: fix (??) REG_CALL_PRIM which was doing some real wrong stuff I have no
 idead why it worked, and if it did work, no idea why it still works after
 my fix...
all the rest: put the ';' at the end of EXTERN_PRIMITIVE(...) as it should 
 have been (or not?)