rewrite popen to use posix_spawn instead of fragile vfork hacks

[musl] / src / stdio / __overflow.c

#include "stdio_impl.h"

int __overflow(FILE *f, int _c)
{
        unsigned char c = _c;
        if (!f->wend && __towrite(f)) return EOF;
        if (f->wpos < f->wend && c != f->lbf) return *f->wpos++ = c;
        if (f->write(f, &c, 1)!=1) return EOF;
        return c;
}