gettext-0.19.8.1 with lto enabled fails on missing log10 in libm (glibc). Tested on 5+ gentoo boxes, with gcc-8.3.0 and gcc-9.1.0. Workaround: disable lto for gettext. Please add this to the lto blocker.
confirmed also in 0.20.0 and 0.20.1
Created attachment 576982 [details, diff] gettext-log10_libm.diff Same here. It doesn't fail with ld=bfd. This patch makes gold/lto possible. There's probably a more sophisticated way by fixing some m4 macro like gettext-tools/gnulib-m4/log10.m4 or such, go figure
I am also hitting this error on 0.20.1, but I don't have lto enabled. :\
Triggered by your issue updates, I've just re-enabled lto for gettext (which is 0.20.1 here now) and can *not* confirm the issue anymore. It seems that having lto on or off is not the whole story.
I am so sorry, I just double-checked and I actually DID have LTO enabled! :\ But enabled in a stupid way, which would not actually do anything beneficial because it was only in LDFLAGS (and not in CFLAGS). Once I disabled that, it compiled and linked fine. Sorry about the red herring.
gettext-0.19.8.1 is not in portage anymore, and the current stable 0.20.1 works for me inclunding lto. So closing.