[ncl-install] Mac OS X 10.11 Incompatability

[Kyle Griffin]

Hi all,

I wanted to highlight the result of a bit of research I've had to do after
upgrading a Mac from 10.9 to 10.11 - specifically, that DYLD_LIBRARY_PATH
and DYLD_FALLBACK_LIBRARY_PATH are no longer supported by default in OS X.
While they can be set, this setting is not recognized in any automated
(cron) calls to scripts. Here's on example output, where I print the
contents of both environmental variables before attempting to run an NCL
script. One environmental variable is set in .profile (manually sourced at
start of the script) and one is set within the script itself. Both are
ignored.

/opt/local/lib/gcc49:/opt/local/lib/gcc

/opt/local/lib/gcc49:/opt/local/lib/gcc

dyld: Library not loaded: /usr/local/lib/libquadmath.0.dylib

  Referenced from: /Users/ksgriffin2/ncl6.3.0.1010/bin/ncl

  Reason: image not found

The dyld:... error was originally missing libgfortran.3.dylib, but I
manually created a link in /usr/local/lib to the version in
/opt/local/lib/gcc49 try and tackle this problem. It appears that linking
libgfortran.3.dylib, libquadmath.0.dylib, and libgomp.1.dylib does the
trick to allow NCL to function as a workaround, but could be problematic
long-term I would guess? The binary in use here is the Mac 10.10/gcc4.9.2
binary.

Apple now claims that any software relying on this should, essentially, not
rely on these techniques any more or place them all in /usr/local/ (I'm
using MacPorts, putting things /opt/local/) [see under last heading on the
page]:
https://developer.apple.com/library/mac/documentation/Security/Conceptual/System_Integrity_Protection_Guide/FileSystemProtections/FileSystemProtections.html#//apple_ref/doc/uid/TP40016462-CH2-DontLinkElementID_2

This can, in theory, be fixed by accessing the system recovery and
disabling the new "System Integrity Protection" feature that eliminates
these issues, but I feel that is not an appropriate fix for this problem.
For testing purposes, the simple process of disabling SIP is presented at
the bottom of this article:
http://www.macworld.com/article/2986118/security/how-to-modify-system-integrity-protection-in-el-capitan.html

I should note the NCL appears to work fine from the command line, although
I have to test it in depth.

So it appears going forward that significant changes may need to be made to
the NCL binaries for OS X in order for them to be functional at all. I'll
be happy to serve as a guinea pig for fixes if a 10.11 system isn't
available for testing...


Kyle
----------------------------------------
Kyle S. Griffin
Department of Atmospheric and Oceanic Sciences
University of Wisconsin - Madison
Room 1407
1225 W Dayton St, Madison, WI 53706
Email: ksgriffin2 at wisc.edu
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