Make pv_error() and pv_perror() available outside of src/pv/, and use them throughout the program.

src/include/pv-internal.h

@@ -554,9 +554,6 @@ struct pvdisplay_component_s {
 	bool dynamic;			 /* whether it can scale with screen size */
 };
 
-void pv_error(char *, ...);
-void pv_perror(char *, ...);
-
 int pv_main_loop(pvstate_t);
 void pv_calculate_transfer_rate(pvtransfercalc_t, readonly_pvtransferstate_t, readonly_pvcontrol_t, readonly_pvdisplay_t, bool);
 

src/include/pv.h

@@ -182,6 +182,17 @@ void pv_nanosleep(long long);
  */
 extern void pv_set_error_prefix(/*@null@ */ const char *);
 
+/*
+ * Report an error.
+ */
+extern void pv_error(char *, ...);
+
+/*
+ * Report an error, suffixed with the system error message for errno.
+ */
+extern void pv_perror(char *, ...);
+
+
 /*
  * Create a new state structure, and return it, or 0 (NULL) on error.
  */