unbreak and eliminate NO_C99_FORMAT

unbreak and eliminate NO_C99_FORMAT

In the spirit of v1.5.0.2~21 (Check for PRIuMAX rather than
NO_C99_FORMAT in fast-import.c, 2007-02-20), use PRIuMAX from
git-compat-util.h on all platforms instead of C99-specific formats
like %zu with dangerous fallbacks to %u or %lu.

So now C99-challenged platforms can build git without provoking
warnings or errors from printf, even if pointers do not have the same
size as an int or long.

The need for a fallback PRIuMAX is detected in git-compat-util.h with
"#ifndef PRIuMAX".  So while at it, simplify the Makefile and configure
script by eliminating the NO_C99_FORMAT knob altogether.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>