MacOS Mojave Version 10.14.5
% uname -a
Darwin NNN.local 18.6.0 Darwin Kernel Version 18.6.0: Thu Apr 25 23:16:27 PDT 2019; root:xnu-4903.261.4~2/RELEASE_X86_64 x86_64
% xcodebuild -version
Xcode 10.2.1
Build version 10E1001
% port installed pdftk gcc5
The following ports are currently installed:
gcc5 @5.5.0_4 (active)
pdftk @2.02_0+gcc5 (active)
% otool -L /opt/local/bin/pdftk
/opt/local/bin/pdftk:
/opt/local/lib/gcc5/libgcj.16.dylib (compatibility version 17.0.0, current version 17.0.0)
/opt/local/lib/libgcc/libstdc++.6.dylib (compatibility version 7.0.0, current version 7.25.0)
/opt/local/lib/libgcc/libgcc_s.1.dylib (compatibility version 1.0.0, current version 1.0.0)
/opt/local/lib/libiconv.2.dylib (compatibility version 9.0.0, current version 9.0.0)
/opt/local/lib/libz.1.dylib (compatibility version 1.0.0, current version 1.2.11)
/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1252.200.5)
Problem:
% pdftk O25a.pdf O26a.pdf cat output TMP
dyld: _dyld_bind_fully_image_containing_address() error
dyld: Symbol not found: __darwin10_Unwind_FindEnclosingFunction
Referenced from: /opt/local/lib/gcc5/libgcj.16.dylib
Expected in: /opt/local/lib/libgcc/libgcc_s.1.dylib
in /opt/local/lib/gcc5/libgcj.16.dylib
Abort trap: 6
https://github.com/macports/macports-ports/pull/4309