Exchange of fprintf(stderr, ...) with avrdude_message(...).

This change was made for the shared library, since library functions
should not write to std-streams directly. Instead avrdude_message()
has to be implemented by the library user. For the avrdude application
this function is implemented in main.c.



git-svn-id: svn://svn.savannah.nongnu.org/avrdude/trunk/avrdude@1305 81a1dc3b-b13d-400b-aceb-764788c761c2

avrdude.h

@@ -28,6 +28,8 @@ extern int ovsigck;		/* override signature check (-F) */
 extern int verbose;		/* verbosity level (-v, -vv, ...) */
 extern int quell_progress;	/* quiteness level (-q, -qq) */
 
+int avrdude_message(const char *format, ...);
+
 #if defined(WIN32NATIVE)
 
 #include "ac_cfg.h"