Get clipboard data from SDL

This makes pasting in client console and UI edit fields work on X11 and OS X.

Sys_GetClipboardData is only used by client, so returning NULL in dedicated is fine.

code/sys/sys_main.c

@@ -127,6 +127,35 @@ char *Sys_ConsoleInput(void)
 	return CON_Input( );
 }
 
+/*
+==================
+Sys_GetClipboardData
+==================
+*/
+char *Sys_GetClipboardData(void)
+{
+#ifdef DEDICATED
+	return NULL;
+#else
+	char *data = NULL;
+	char *cliptext;
+
+	if ( ( cliptext = SDL_GetClipboardText() ) != NULL ) {
+		if ( cliptext[0] != '\0' ) {
+			size_t bufsize = strlen( cliptext ) + 1;
+
+			data = Z_Malloc( bufsize );
+			Q_strncpyz( data, cliptext, bufsize );
+
+			// find first listed char and set to '\0'
+			strtok( data, "\n\r\b" );
+		}
+		SDL_free( cliptext );
+	}
+	return data;
+#endif
+}
+
 #ifdef DEDICATED
 #	define PID_FILENAME PRODUCT_NAME "_server.pid"
 #else