Compiling gcc - unknown conversion type

[NightStrike]

When I compile gcc to target x86_64-pc-mingw32 using either
x86_64-pc-linux (FC8) or i686-pc-linux (Gentoo) as the build/host
systems, I see a large number of warnings that are all similar to:

../../gcc/gcc/builtins.c: In function 'expand_builtin':
../../gcc/gcc/builtins.c:6292: warning: unknown conversion type
character 'K' in format
../../gcc/gcc/builtins.c:6292: warning: too many arguments for format
../../gcc/gcc/builtins.c:6298: warning: unknown conversion type
character 'K' in format
../../gcc/gcc/builtins.c:6298: warning: too many arguments for format


Any idea on the cause of these?