Move support for %h prefixed format specifiers

[lgrahl]

The patch has been rejected in creytiv#49. There is no way to resolve this problem without either replacing all macros or setting a handler to handle this format specifier. However, currently there is no unknown format specifier handler - only a proposal in creytiv#51.

See branch support-fmt-h.

[lgrahl]

The proposal has been rejected (actually, quite a long time ago). Replacing portable format specifiers with non-portable specifiers is out of the question for me.

I'm out of ideas. If someone sees a solution that libre maintainers could possibly accept, please go for it. Otherwise, it leaves us with no choice but to keep and maintain this fork, at least for that specific branch.