rg: artist only if credit differs

src/awk/releasegroups.awk

@@ -3,7 +3,6 @@ BEGIN { OFS="\t" }
 {
   line_type=""
   line_sectype=""
-  line_release=format_release
   line_year=""
   gsub("&", "\\\\&")
   id = $1
@@ -11,7 +10,8 @@ BEGIN { OFS="\t" }
   sectype = $3
   year = substr($4, 1, 4) + 0
   title = $5
-  artist = $6
+  artistcredit = $6
+  line_release = artist==artistcredit ? format_release : format_release_w_artist
   switch (type) {
     case "Single": line_type=format_single; break
     case "Album": line_type=format_album; break
@@ -45,7 +45,7 @@ BEGIN { OFS="\t" }
     line_sectype = sprintf(format_secondary, line_sectype)
   }
   sub("<<title>>", title, line_release)
-  sub("<<artist>>", artist, line_release)
+  sub("<<artist>>", artistcredit, line_release)
   line_year = year ? format_year : ""
   sub("<<year>>", year, line_year)
   sort = year ? year : 0