Comply with compiler warnings

dpi.c

@@ -9,12 +9,12 @@
 
 int dpi_check_auth(int fd) {
 	char buf[30];
-	char key[4], local_key[4];
+	unsigned key[4], local_key[4];
 	char keys[128];
 	char *home;
 	ssize_t sz;
 	int rc;
-	rc = read_all(fd, buf, 28);
+	rc = read_all(fd, (unsigned char *)buf, 28);
 	if (rc < 0) return -1;
 	buf[29] = '\0';
 	// first byte was read already
@@ -34,9 +34,9 @@ int dpi_read_request(int fd, char *url_buf, size_t url_len) {
 	char buf[21];
 	size_t len;
 	int rc;
-	int i;
+	size_t i;
 
-	rc = read_all(fd, buf, sizeof(buf));
+	rc = read_all(fd, (unsigned char *)buf, sizeof(buf));
 	if (rc < 0 && errno == EPIPE && !strncmp(buf, "<cmd='DpiBye' '>", 16)) {
 		errno = ESHUTDOWN;
 		return -1;
@@ -47,7 +47,7 @@ int dpi_read_request(int fd, char *url_buf, size_t url_len) {
 		return -1;
 	}
 	len = url_len;
-	rc = read_some(fd, url_buf, &len);
+	rc = read_some(fd, (unsigned char *)url_buf, &len);
 	if (rc < 0) return -1;
 
 	for (i = 0; i < len-1; i++) {