Comment 32 for bug 1863162

i have a new patch set that includes a different fix for this bug:
https://sourceware.org/pipermail/libc-alpha/2021-February/122626.html

the new fix takes the dlopen lock at thread creation time instead
of just using atomics (which cannot work for fixing the same race
with dlclose: bug 27111).

using atomics is still necessary for tls access.

it will likely take a few review iterations to get this in glibc.