cmdutils: make this_year extern, so it can be referenced from other .o files

Required by a pending change in ffprobe.

cmdutils.c

@@ -54,7 +54,7 @@
 struct SwsContext *sws_opts;
 AVDictionary *format_opts, *codec_opts;
 
-static const int this_year = 2012;
+const int this_year = 2012;
 
 static FILE *report_file;
 

cmdutils.h

@@ -43,6 +43,11 @@ extern const char program_name[];
  */
 extern const int program_birth_year;
 
+/**
+ * this year, defined by the program for show_banner()
+ */
+extern const int this_year;
+
 extern AVCodecContext *avcodec_opts[AVMEDIA_TYPE_NB];
 extern AVFormatContext *avformat_opts;
 extern struct SwsContext *sws_opts;