doxygen @1.9.5 upgrade failure on 10.13.6: error: call to unavailable function 'get': introduced in macOS 10.14

[rufty (Bill Hill)]

doxygen fails to complete the build on OSX 10.13.6, MP 2.8.0

:info:build [ 54%] Built target vhdlparser
:info:build make[1]: Leaving directory `/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_textproc_doxygen/doxygen/work/doxygen-1.9.5'
:info:build make: *** [all] Error 2
:info:build make: Leaving directory `/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_textproc_doxygen/doxygen/work/doxygen-1.9.5'
:info:build Command failed:  cd "/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_textproc_doxygen/doxygen/work/doxygen-1.9.5" && /usr/bin/make -j2 -w all VERBOSE=ON 
:info:build Exit code: 2
:error:build Failed to build doxygen: command execution failed
:debug:build Error code: CHILDSTATUS 1029 2
:debug:build Backtrace: command execution failed
:debug:build     while executing
:debug:build "system {*}$notty {*}$callback {*}$nice $fullcmdstring"
:debug:build     invoked from within
:debug:build "command_exec -callback portprogress::target_progress_callback build"
:debug:build     (procedure "portbuild::build_main" line 8)
:debug:build     invoked from within
:debug:build "$procedure $targetname"
:error:build See /opt/local/var/macports/logs/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_textproc_doxygen/doxygen/main.log for details.

[rufty (Bill Hill)]

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