Revert the changes to os0file.c that were accidentally committed in r181:

os_file_create_tmpfile(): Replace the UNIV_HOTBACKUP specific
implementation with a run-time assertion failure.

os/os0file.c

@@ -518,36 +518,61 @@ os_file_create_tmpfile(void)
 /*========================*/
 			/* out: temporary file handle, or NULL on error */
 {
-#ifdef UNIV_HOTBACKUP
-	ut_error;
-
-	return(NULL);
-#else
-# ifdef __NETWARE__
+#ifdef __NETWARE__
 	FILE*	file	= tmpfile();
-# else /* __NETWARE__ */
+#else /* __NETWARE__ */
 	FILE*	file	= NULL;
-	int	fd	= innobase_mysql_tmpfile();
+	int	fd	= -1;
+# ifdef UNIV_HOTBACKUP
+	int	tries;
+	for (tries = 10; tries--; ) {
+		char*	name = tempnam(fil_path_to_mysql_datadir, "ib");
+		if (!name) {
+			break;
+		}
+
+		fd = open(name,
+#  ifdef __WIN__
+			O_SEQUENTIAL | O_SHORT_LIVED | O_TEMPORARY |
+#  endif /* __WIN__ */
+			O_CREAT | O_EXCL | O_RDWR,
+			S_IREAD | S_IWRITE);
+		if (fd >= 0) {
+#  ifndef __WIN__
+			unlink(name);
+#  endif /* !__WIN__ */
+			free(name);
+			break;
+		}
+
+		ut_print_timestamp(stderr);
+		fprintf(stderr, "  InnoDB: Warning: "
+			"unable to create temporary file %s, retrying\n",
+			name);
+		free(name);
+	}
+# else /* UNIV_HOTBACKUP */
+	fd = innobase_mysql_tmpfile();
+# endif /* UNIV_HOTBACKUP */
 
 	if (fd >= 0) {
 		file = fdopen(fd, "w+b");
 	}
-# endif /* __NETWARE__ */
+#endif /* __NETWARE__ */
 
 	if (!file) {
 		ut_print_timestamp(stderr);
 		fprintf(stderr,
 			"  InnoDB: Error: unable to create temporary file;"
 			" errno: %d\n", errno);
-# ifndef __NETWARE__
+#ifndef __NETWARE__
 		if (fd >= 0) {
 			close(fd);
 		}
-# endif /* !__NETWARE__ */
+#endif /* !__NETWARE__ */
 	}
 
 	return(file);
-#endif /* UNIV_HOTBACKUP */
 }
 
 /***************************************************************************