reorganization in rev 1.16 of i386/include/types.h which changed
stdlib.h's use of <machine/types.h>. The problem was the -I. was causing
machine/types.h to come from the current kernel source, while stdlib.h was
coming from /usr/include. /usr/include/stdlib.h is as old as the last
'make world', the machine/types.h was as new as the current source.