For me on ppc64le, the latest opus creates man3 packages.  Assuming you want to package them, the following patch to the opus spec may be helpful:

[baude@ppc64le opus]$ git diff
diff --git a/opus.spec b/opus.spec
index dbf1a35..bc291b1 100644
--- a/opus.spec
+++ b/opus.spec
@@ -56,6 +56,7 @@ rm -rf %{buildroot}
 %defattr(-,root,root,-)
 %doc COPYING README rfc6716.txt
 %{_libdir}/libopus.so.*
+%{_mandir}/man3/*
 
 %files devel
 %defattr(-,root,root,-)