The latest version of csurf:

  csurf0.8-mac-151116.tgz

now works correctly on Max OS X 10.11 (tested on
10.11.0 and 10.11.1), as well as on all earlier
versions going back to Max OS X 10.6.8.

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Details
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The new El Capitan System Integrity Protection,
SIP, no longer passes some shell environment
variables to subshells (e.g., $PATH and
$DYLD_LIBRARY_PATH are not passed).  The first
line of csurf was:

  #! /usr/bin/env wish8.5

which relied on $PATH being passed to the
subshell so the right X11 wish8.5 gets called,
and also on $DYLD_LIBRARY_PATH being passed so
that the csurf-internal tcl libs get used.

Here is the workaround which avoids a subshell
(works on older shells):

  #! /bin/sh
  # next b/c Mac 10.11 doesn't pass DYLD_LIBRARY_PATH to subshell \
  DYLD_LIBRARY_PATH=$CSURF_LIBRARY_PATH exec wish8.5 $0 ${1+"$@"}

The env command was also being using to start
tksurfer, since some variables were being passed
as environment variables to tcl scripts.  I now
pass those variables using a tmpfile.

Hopefully, this csurf update will last more than
one day :-}