Make tilde render as a tilde

dosp-survey.ltx

@@ -272,7 +272,8 @@ code reuse in proprietary software projects, but only for a limited
 time, something Zooko characterized as a compromise between
 permissive and reciprocal open source licensing models.\footnote{See,
 for example, the presentation at
-\otsurl{https://tahoe-lafs.org/~zooko/tgppl.pdf}.}
+\otsurl{https://tahoe-lafs.org/\textasciitilde{}zooko/tgppl.pdf}.}
+% TODO: Get rid of the {} that shows up in the link target
 
 Since both the start and end-state licenses of the BOSL are themselves
 open source, we do not regard the BOSL as a form of delayed open source