The gcc compiler incorrectly detects support for the CPUID instruction on first generation i80486 processors (which lack it). This causes most programs linked to libgcc_s.so.1 to error out. Unfortunately, that is a huge number of programs. This has been fixed in upstream gcc versions 5.x, 6.x, and 7.x. Please backport the patch or upgrade. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68491
I am rather doubtful that anyone would be running Gentoo on a i486 these days, so this hardly seems worth a backport.
I am running on an i486 for regression testing. Testing on old hardware has turned up some bugs that were worth fixing (see "nohz problem with idle time on old hardware" on linux kernel mailing list for an example). While not particularly interesting, the upstream gcc team thought it was worth fixing and backporting.
GCC 6.4.0 already has the fix. I would guess a 7.2.0 release is due soon. 5.5.0 is probably farther off, if it even happens.
(In reply to Mike Gilbert from comment #3) > GCC 6.4.0 already has the fix. I would guess a 7.2.0 release is due soon. > 5.5.0 is probably farther off, if it even happens. 6.4 and 7.2 are in Gentoo, and 6.4.0 will get stabilized soon.
6.4.0 is stable everywhere.