fix building w/jbig-2.x

--- a/converter/other/jbig/jbigtopnm.c
+++ b/converter/other/jbig/jbigtopnm.c
@@ -230,8 +230,12 @@ int main (int argc, char **argv)
     if (ferror(fin)) 
         pm_error("Problem while reading input file '%s", fnin);
     if (result != JBG_EOK && result != JBG_EOK_INTR) 
-        pm_error("Problem with input file '%s': %s\n", 
-                 fnin, jbg_strerror(result, JBG_EN));
+        pm_error("Problem with input file '%s': %s\n", fnin,
+#ifdef JBG_EN
+                 jbg_strerror(result, JBG_EN));
+#else
+                 jbg_strerror(result));
+#endif
     if (plane >= 0 && jbg_dec_getplanes(&s) <= plane) 
         pm_error("Image has only %d planes!\n", jbg_dec_getplanes(&s));