[Bug lto/78562] Wrong warning for built-in functions with -flto

[gjl at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78562

--- Comment #5 from Georg-Johann Lay <gjl at gcc dot gnu.org> ---
Maybe it is an option to be less strict?  In the test case, both function name
and asm name (libname) are in the namespace of the implementation: both start
with 2 underscores.  The function name even starts with __builtin_...