Support commas?

[simonhf]

I tried changing the test file to:

#include <locale.h>
...
setlocale(LC_NUMERIC, "");
TPRINTF("%'llu\n", ULLONG_MAX);

But the output is:

$ make
...
libc_printf("%'llu\n", ULLONG_MAX) -> 18,446,744,073,709,551,615
 tfp_printf("%'llu\n", ULLONG_MAX) -> llu
...

The commas display for glibc as expected, but not for tfp. Any chance of adding comma support? Or at least understanding the ' character even if commas are not printed? If the locale stuff is too OTT for tinyprintf(), how about enabling comma support via an environment variable instead?