bug#68871: Can't use od to print half-precision floats

[Paul Eggert]

Oh, and another thought: suppose someone wants to use od on bfloat16_t 
values? They're popular in machine learning applications, and likely 
will be more popular than float16_t overall. See:

https://sourceware.org/pipermail/libc-alpha/2024-February/154382.html