[tlbuild] Repeated Mac arm64 crashes of xdvi-xaw with "set_no_char: attempt to set character of unknown font, offset 42"

[Nelson H. F. Beebe]

Another possibility is to link xdvi-xaw with the Electric Fence
library, -lefence.  Many O/S distributions have it (Red Hat:
ElectricFence.x86_64, Ubuntu 20.04: electric-fence, FreeBSD:
electricfence, ...).

The link https://directory.fsf.org/wiki/Electric_Fence for source code
points to http://perens.com/FreeSoftware/ElectricFence/, but that link
is currently broken.

You control ElectricFence by defining environment variables, and
unlike valgrind, the program runs at normal speed, with debug reports
only produced when memory violations are observed.  Ater installation,
"man efence" gives details.

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- Nelson H. F. Beebe                    Tel: +1 801 581 5254                  -
- University of Utah                    FAX: +1 801 581 4148                  -
- Department of Mathematics, 110 LCB    Internet e-mail: beebe at math.utah.edu  -
- 155 S 1400 E RM 233                       beebe at acm.org  beebe at computer.org -
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