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.
