[Bug lto/48200] Implement function attribute for symbol versioning (.symver)

[mark at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=48200

--- Comment #45 from Mark Wielaard <mark at gcc dot gnu.org> ---
Note that the hack in comment 43 doesn't really work with elfutils since the
.symver attribute doesn't work exactly like the assembly construct with @@@.
The @@@ symver variant see https://sourceware.org/binutils/docs/as/Symver.html

The third usage of the .symver directive is:

.symver name, name2@@@nodename

When name is not defined within the file being assembled, it is treated as
name2@nodename. When name is defined within the file being assembled, the
symbol name, name, will be changed to name2@@nodename. 

Which means it is renamed, so that it doesn't clash when used in a version map
file.