io: Add set_log_io_errors().

This function allows disabling of error messages from fdwrite,
fdread and fdgetline functions.

io.c

 #include <stdio.h>
 #include <stdlib.h>
 #include <stdarg.h>
+#include <stdbool.h>
 #include <unistd.h>
 #include <string.h>
 #include <netdb.h>
 #include "libfuncs.h"
 #include "log.h"
 
+static int io_report_errors = 1;
+
+void set_log_io_errors(int report_io_errors) {
+	io_report_errors = report_io_errors;
+}
+
 char * chomp(char *x) {
 	int i=strlen(x)-1;
 	while ((i>=0)&&((x[i]=='\n')||(x[i]=='\r')||(x[i]==' ')||(x[i]=='\t'))){
 			if (num_timeouts++ <= FDGETLINE_RETRIES) {
 				continue;
 			} else {
-				log_perror("fdgetline() timeout", errno);
+				if (io_report_errors)
+					log_perror("fdgetline() timeout", errno);
 			}
 		}
 		if (fdready == 0 || fdready == -1) { /* Timeout || error */
 			if (num_timeouts++ <= retries) {
 				continue;
 			} else {
-				if (timeout) {
+				if (timeout && io_report_errors) {
 					log_perror("fdread() timeout", errno);
 				}
 				return rbytes > 0 ? rbytes : -1;
 			if (num_timeouts++ <= FDWRITE_RETRIES) {
 				continue;
 			} else {
-				log_perror("fdwrite() timeout", errno);
+				if (io_report_errors)
+					log_perror("fdwrite() timeout", errno);
 				return wbytes > 0 ? wbytes : -1;
 			}
 		}

io.h

 int fdputs(int fd, char *msg);
 int fdputsf(int fd, char *fmt, ...);
 
+void set_log_io_errors(int report_io_errors);
+
 void set_sock_nonblock(int sockfd);
 void set_sock_block(int sockfd);