refactor headers, especially alltypes.h, and improve C++ ABI compat

[musl] / src / internal / syscall_ret.c

#include <errno.h>
#include <unistd.h>

long __syscall_ret(unsigned long r)
{
        if (r > -4096UL) {
                errno = -r;
                return -1;
        }
        return r;
}