OSX/CI: external project poppler fails to build

[Marko Käning]

When trying to build the external project poppler on OSX/CI it fails currently although libiconv is installed:
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$ port installed libiconv
The following ports are currently installed:
  libiconv @1.14_0 (active)
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.
.
.
[ 69%] Building CXX object qt5/src/CMakeFiles/poppler-qt5.dir/poppler-page.cc.o
[ 70%] Building CXX object cpp/CMakeFiles/poppler-cpp.dir/poppler-version.cpp.o
[ 71%] Building CXX object cpp/CMakeFiles/poppler-cpp.dir/poppler-private.cpp.o
/Users/marko/WC/KDECI-builds/poppler/qt5/src/poppler-page.cc:77:12: warning: enumeration value 'actionOCGState' not handled in switch [-Wswitch]
  switch ( a->getKind() )
           ^
Linking CXX shared library libpoppler-cpp.dylib
Undefined symbols for architecture x86_64:
  "_libiconv", referenced from:
      poppler::ustring::to_utf8() const in poppler-global.cpp.o
      poppler::ustring::from_utf8(char const*, int) in poppler-global.cpp.o
  "_libiconv_close", referenced from:
      (anonymous namespace)::MiniIconv::~MiniIconv() in poppler-global.cpp.o
  "_libiconv_open", referenced from:
      (anonymous namespace)::MiniIconv::MiniIconv(char const*, char const*) in poppler-global.cpp.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make[2]: *** [cpp/libpoppler-cpp.0.2.0.dylib] Error 1
make[1]: *** [cpp/CMakeFiles/poppler-cpp.dir/all] Error 2
make[1]: *** Waiting for unfinished jobs....
1 warning generated.
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Any ideas?