POSIX specifies the C conversion specifier as being "equivalent to %lc",
i.e. printf("%C", arg) is equivalent in behaviour to printf("%lc", arg).
This patch implements this conversion specifier, and adds a test for it,
alongside another test, which ensures that va_arg uses the correct size,
even though we set signbit to 63 in the code (which one might think will
result in the wrong size of argument being va_arg-ed, but having signbit
set to 63 is in fact what __fmt_stoa expects and is a requirement for it
properly formatting the wchar_t argument - this does not result in wrong
usage of va_arg because the implementation of the c conversion specifier
(which the implementation of the C conversion specifier fallsthrough to)
always calls va_arg with an argument type of int, to avoid the very same
bug occuring with %lc, as the l length modifier also sets signbit to 63)
Cosmopolitan's printf-family functions currently very poorly handle
being passed a long double infinity.
For instance, a program such as:
```cpp
#include <stdio.h>
int main()
{
printf("%f\n", 1.0 / 0.0);
printf("%Lf\n", 1.0L / 0.0L);
printf("%e\n", 1.0 / 0.0);
printf("%Le\n", 1.0L / 0.0L);
printf("%g\n", 1.0 / 0.0);
printf("%Lg\n", 1.0L / 0.0L);
}
```
will currently output the following:
```
inf
0.000000[followed by 32763 more zeros]
inf
N.aN0000e-32769
inf
N.aNe-32769
```
when the correct expected output would be:
```
inf
inf
inf
inf
inf
inf
```
This patch fixes this, and adds tests for the behavior.
At least in neovim, `│vi:` is not recognized as a modeline because it
has no preceding whitespace. After fixing this, opening a file yields
an error because `net` is not an option. (`noet`, however, is.)
The stdio reader thread now appears to be working recursively along
cosmopolitan subprocesses. For example, it's now possible to launch
vim.com from the unbourne.com bestline repl, thanks to hacks plus a
bug fix to select() timeouts.
