[Bug lto/49664] liblto_plugin.so exports too many symbols

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=49664

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Created attachment 51440
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=51440&action=edit
Patch which at least builds correctly in lto-plugin

The previous patch I had a typo where I had put oncall instead of the correct
onload.

Anyways this fixes the issue and libtool does the rest.