tag/TagId3: eliminate dummy function when libid3tag is disabled

src/tag/Generic.cxx

@@ -40,10 +40,14 @@ ScanGenericTags(InputStream &is, const TagHandler &handler, void *ctx)
 	if (tag_ape_scan2(is, handler, ctx))
 		return true;
 
+#ifdef ENABLE_ID3TAG
 	if (!is.Rewind(IgnoreError()))
 		return false;
 
 	return tag_id3_scan(is, handler, ctx);
+#else
+	return false;
+#endif
 }
 
 /**

src/tag/TagId3.hxx

@@ -21,15 +21,12 @@
 #define MPD_TAG_ID3_HXX
 
 #include "check.h"
-#include "Compiler.h"
 
 class InputStream;
 struct TagHandler;
 struct Tag;
 struct id3_tag;
 
-#ifdef ENABLE_ID3TAG
-
 bool
 tag_id3_scan(InputStream &is,
 	     const TagHandler &handler, void *handler_ctx);
@@ -45,16 +42,4 @@ void
 scan_id3_tag(id3_tag *tag,
 	     const TagHandler &handler, void *handler_ctx);
 
-#else
-
-static inline bool
-tag_id3_scan(gcc_unused InputStream &is,
-	     gcc_unused const TagHandler &handler,
-	     gcc_unused void *handler_ctx)
-{
-	return false;
-}
-
-#endif
-
 #endif