Comment 3 for bug 1710375

This is on a 32-bit Gentoo box. I've done git bisect and found that the commit which has introduced this Memory fault at (nil) problem is

grozin@elrond ~/sbcl $ git bisect bad
f4e758d44524b25ae23cafadb2f5eda76323f4dd is the first bad commit
commit f4e758d44524b25ae23cafadb2f5eda76323f4dd
Author: Douglas Katzman <email address hidden>
Date: Tue May 2 19:15:33 2017 -0400

    Give user more control over C compiler flags in src/runtime.

    And though make-target-contrib.sh clears EXTRA_CFLAGS, append them
    in contrib/asdf-module.mk instead of assigning,
    to allow driving the contribs build step differently.

How can I find more useful information?