it was my intent to run this change by you before committing it, but
it was part of a large diff collection which ignatios has been chewing
through and revieweing.

The "right" answer here appears to be to define a "format checking"
function in libc, which verifies that two formats are "compatible"
with respect to what arguments they expect.  the function would be
declared to be a format pass-through function (like gettext or catgets).

A number of the more intractable format-checking problems would be
solved by this; libusb could then use that function to check that the
supplied format was compatible with "%s".

usage would look something like:

	snprintf(buf, sizeof(buf), fmtcheck(user_supplied_format, "%s%d"),
		"string", NUMBER);

synopsys:

char *fmtcheck(const char *f1, const char *f2):

if f1 and f2 are compatible format strings, f1 is be returned;
otherwise f2 is returned.

					- Bill