[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 #4 from Georg-Johann Lay <gjl at gcc dot gnu.org> ---
(In reply to rguenther@suse.de from comment #3)
> Yes, using aliases would be a good workaround.

hmmm, for libgcc functions written in asm this is easy enough, like

.global func1_alias
.global func1

func1_alias:
func1:
   ;; asm-code

But how can I define an extra symbol for a libgcc function if that function is
written in C? E.g. __countlshi2 from libgcc/config/avr/lib2funcs.c.