Unable to set DYLD_FALLBACK_LIBRARY_PATH in shell on OSX 10.11.1

In shell scripts used for unit testing with dynamic libraries in a directory other than the typical @rpath, I have previously been able to set DYLD_FALLBACK_LIBRARY_PATH to set the directory containing the libraries. Under 10.11.1, bash seems to ignore attempts to set this environment variable: $ sh -x testscript.sh + DYLD_FALLBACK_LIBRARY_PATH=/Users/something/testinglibs + export DYLD_FALLBACK_LIBRARY_PATH + exec printenv and DYLD_FALLBACK_LIBRARY_PATH is not present in printenv's output. Is this a security-related hack in 10.11's shell? I haven't been able to find this change documented in man pages or online.