progress meter: move file name to bb_progress_t. +20 bytes

We were doing expensive unicode conversion on every update

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/include/libbb.h b/include/libbb.h
index c017880..7581cd4 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -1587,15 +1587,21 @@
 	off_t lastsize;
 	unsigned lastupdate_sec;
 	unsigned start_sec;
-	smallint inited;
+	const char *curfile;
 } bb_progress_t;
 
-void bb_progress_init(bb_progress_t *p) FAST_FUNC;
-void bb_progress_update(bb_progress_t *p, const char *curfile,
+#define is_bb_progress_inited(p) ((p)->curfile != NULL)
+#define bb_progress_free(p) do { \
+	if (ENABLE_UNICODE_SUPPORT) free((char*)((p)->curfile)); \
+	(p)->curfile = NULL; \
+} while (0)
+void bb_progress_init(bb_progress_t *p, const char *curfile) FAST_FUNC;
+void bb_progress_update(bb_progress_t *p,
 			uoff_t beg_range,
 			uoff_t transferred,
 			uoff_t totalsize) FAST_FUNC;
 
+
 extern const char *applet_name;
 
 /* Some older linkers don't perform string merging, we used to have common strings