tar et al: die if bb_copyfd_size copies less than asked for.

(we have bb_copyfd_exact_size now for that kind of usage)

archival/libunarchive/data_extract_to_stdout.c

@@ -4,9 +4,11 @@
  */
 
 #include "unarchive.h"
-#include <unistd.h>
+//#include <unistd.h>
 
 void data_extract_to_stdout(archive_handle_t *archive_handle)
 {
-	bb_copyfd_size(archive_handle->src_fd, STDOUT_FILENO, archive_handle->file_header->size);
+	bb_copyfd_exact_size(archive_handle->src_fd,
+			STDOUT_FILENO,
+			archive_handle->file_header->size);
 }