[PATCH] fix for inconsistent output of spprintf() (for %p specifier)

Hello folks,
In all functions using spprintf(), the output corresponding to the
format conversion specifier "%p" depends on the value of the
previously converted argument (if any), not just the pointer
corresponding to the specifier.

1. If the previously-converted argument was a non-zero integer, the
   hexadecimal string value will be correctly prefixed with "0x".
2. If there was no previously-converted argument, or if it was zero or a
   non-integer, the "0x" hexadecimal prefix will be missing.

The attached patch fixes this problem, as also reported in bug #28012
http://bugs.php.net/bug.php?id=28012

It's clearly the most minor of minor bugs but the output of %p has
puzzled me for a while and I decided today to track it down. Hope this
helps!

Thanks,
Eric Lambart