Add special version identification and Gentoo contact information,
in order to fulfil provisions 2 through 4 of the gnuplot licence.

--- gnuplot-orig/src/plot.c
+++ gnuplot/src/plot.c
@@ -383,9 +383,11 @@
 		    "  -V, --version\n"
 		    "  -h, --help\n"
 		    "  -e  \"command1; command2; ...\"\n"
-		    "gnuplot %s patchlevel %s\n"
-		    "Report bugs to %s\n",
-		    gnuplot_version, gnuplot_patchlevel, bug_email);
+		    "gnuplot %s patchlevel %s (Gentoo revision %s)\n"
+		    "Report bugs to <%s>\n"
+		    "or to <%s>\n",
+		    gnuplot_version, gnuplot_patchlevel, gentoo_revision,
+		    gentoo_bugtracker, bug_email);
 	    return 0;
 	}
     }
--- gnuplot-orig/src/show.c
+++ gnuplot/src/show.c
@@ -1052,7 +1052,7 @@
 
     fprintf(fp, "%s\n\
 %s\t%s\n\
-%s\tVersion %s patchlevel %s\n\
+%s\tVersion %s patchlevel %s (Gentoo revision %s)\n\
 %s\tlast modified %s\n\
 %s\tSystem: %s %s\n\
 %s\n\
@@ -1063,10 +1063,11 @@
 %s\tThe gnuplot FAQ is available from %s\n\
 %s\n\
 %s\tSend bug reports and suggestions to <%s>\n\
+%s\tor to <%s>\n\
 %s\n",
 	    p,			/* empty line */
 	    p, PROGRAM,
-	    p, gnuplot_version, gnuplot_patchlevel,
+	    p, gnuplot_version, gnuplot_patchlevel, gentoo_revision,
 	    p, gnuplot_date,
 	    p, os_name, os_rel,
 	    p,			/* empty line */
@@ -1076,6 +1077,7 @@
 	    p,			/* Type `help` */
 	    p, faq_location,
 	    p,			/* empty line */
+	    p, gentoo_bugtracker,
 	    p, bug_email,
 	    p);			/* empty line */
 
--- gnuplot-orig/src/version.c
+++ gnuplot/src/version.c
@@ -46,6 +46,9 @@
 
 const char faq_location[] = FAQ_LOCATION;
 
+const char gentoo_revision[] = GENTOO_REVISION;
+const char gentoo_bugtracker[] = "http://bugs.gentoo.org/";
+
 char *compile_options = (void *)0;	/* Will be loaded at runtime */
 
 #define RELEASE_VERSION 1
--- gnuplot-orig/src/version.h
+++ gnuplot/src/version.h
@@ -47,6 +47,9 @@
 extern const char bug_email[];
 extern const char help_email[];
 
+extern const char gentoo_revision[];
+extern const char gentoo_bugtracker[];
+
 extern char os_name[];
 extern char os_rel[];