assume that runes are format (but not flags). this allows a format of Γ to yield this warning: 8c -FTVw vmx.c warning: vmx.c:2845 format mismatch 13Γ VLONG, arg 4 rather than the somewhat obtuse warning: vmx.c:2845 format mismatch 13 VLONG, arg 4 for the format "%13Γ".