This appears to me to be fixed in bionic-updates with gcc-7 7.3.0-27ubuntu1~18.04. I'm marking this as no longer affecting me.
** Changed in: gcc-7 (Ubuntu Bionic) Status: In Progress => Fix Released -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1770342 Title: afl no longer builds from source with gcc-7; doesn't look for "as" in dir specified by -B To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gcc-7/+bug/1770342/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs