When LD_PRELOAD is defined (which can be a consequence of gtk3-nocsd
being installed and the user being in an X11 session), I get:

zira:~> gcc -fsanitize=address t.c
zira:~> ./a.out
==11059==ASan runtime does not come first in initial library list; you should either link runtime to your application or manually preload it with LD_PRELOAD.

Note also that this isn't even documented.

BTW, in my case (LD_PRELOAD=libgtk3-nocsd.so.0), libgtk3-nocsd.so.0
is completely unrelated to the program, thus this is a spurious
error.

Dear submitter,

as the package gcc-9 has just been removed from the Debian archive
unstable we hereby close the associated bug reports.  We are sorry
that we couldn't deal with your issue properly.

For details on the removal, please see https://bugs.debian.org/1076502

The version of this package that was in Debian prior to this removal
can still be found using https://snapshot.debian.org/.

Please note that the changes have been done on the master archive and
will not propagate to any mirrors until the next dinstall run at the
earliest.

This message was generated automatically; if you believe that there is
a problem with it please contact the archive administrators by mailing
ftpmaster@ftp-master.debian.org.

Debian distribution maintenance software
pp.
Scott Kitterman (the ftpmaster behind the curtain)

Control: reopen -1
Control: reassign -1 libasan8 14.1.0-5
[...]

Instead of closing the bug, let's reassign it to the current
package name (the problem is still there).

Control: retitle -1 libasan8: AddressSanitizer breaks when LD_PRELOAD is defined
Control: found -1 15.2.0-12

Adjust bug title.