Bug 42175

	The libc_r version of select(2) doesn't check for error conditions
	on the file descriptor for readability or writability. So it's possible
	for select() to return zero, yet no file descriptor bits are set.

How-To-Repeat: 
	Compile and run this program first linking with libc, then with
	libc_r:

	$ cc -Wall -o xx xx.c
	$ cc -Wall -o xxp xx.c -D_THREAD_SAFE -pthread

	$ ./xx
	press ctrl-c...
	^Cxx: select: Bad file descriptor
	$ ./xxp
	press ctrl-c...
	^Cstdin readable=0

	Notice in the second case, select() returned OK but stdin
	was not marked readable.

============================== CUT HERE ================================

#ifdef __linux__
#define _XOPEN_SOURCE   600
#define _GNU_SOURCE     1
#define _BSD_SOURCE     1
#define _ISOC99_SOURCE  1
#endif

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <netinet/in.h>
#include <netinet/tcp.h>

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <signal.h>
#include <fcntl.h>
#include <errno.h>
#include <unistd.h>
#include <time.h>
#include <err.h>

static void	handler(int sig);

int
main(int ac, char **av)
{
	fd_set fds;

	printf("press ctrl-c...\n");
	signal(SIGINT, handler);
	FD_ZERO(&fds);
	FD_SET(0, &fds);
	while (1) {
		if (select(1, &fds, NULL, NULL, NULL) == -1) {
			if (errno != EINTR)
				err(1, "select");
			continue;
		}
		break;
	}
	printf("stdin readable=%d\n", FD_ISSET(0, &fds) != 0);

	/* Done */
	return (0);
}

static void
handler(int sig)
{
	if (close(0) == -1)
		err(1, "close");
}

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