Obexfs fails to compile properly with LDFLAGS="-Wl,--as-needed" because it tries to link openobex before linking obexftp, and as such drops openobex first and then fails to find symbols when linking in obexftp. The patch simply changes the re-ordering (don't forget to eautomake in the ebuild). Patch to follow.
Created attachment 83824 [details, diff] obexfs-0.7-as-needed.patch
fixed in obexfs-0.8. thanks!