Bug#1007891: calligra FTBFS with poppler 22.02

[Adrian Bunk <bunk@debian.org>]

Source: calligra
Version: 1:3.2.1+dfsg-4
Severity: serious
Tags: ftbfs fixed-upstream
Control: block 1006233 by -1

https://buildd.debian.org/status/logs.php?pkg=calligra&ver=1%3A3.2.1%2Bdfsg-4%2Bb2

...
In file included from /usr/include/poppler/PDFDoc.h:62,
                 from /<<PKGBUILDDIR>>/filters/karbon/pdf/PdfImport.cpp:39:
/usr/include/poppler/Form.h:326:10: error: ‘optional’ in namespace ‘std’ does not name a template type
  326 |     std::optional<GooString> getCheckedSignature(Goffset *checkedFileSize);
      |          ^~~~~~~~
/usr/include/poppler/Form.h:326:5: note: ‘std::optional’ is only available from C++17 onwards
  326 |     std::optional<GooString> getCheckedSignature(Goffset *checkedFileSize);
      |     ^~~
/usr/include/poppler/Form.h:619:10: error: ‘optional’ in namespace ‘std’ does not name a template type
  619 |     std::optional<GooString> getCheckedSignature(Goffset *checkedFileSize);
      |          ^~~~~~~~
/usr/include/poppler/Form.h:619:5: note: ‘std::optional’ is only available from C++17 onwards
  619 |     std::optional<GooString> getCheckedSignature(Goffset *checkedFileSize);
      |     ^~~
make[3]: *** [filters/karbon/pdf/CMakeFiles/calligra_filter_pdf2svg.dir/build.make:107: filters/karbon/pdf/CMakeFiles/calligra_filter_pdf2svg.dir/PdfImport.cpp.o] Error 1


The Ubuntu diff seems to contain the changes necessary to fix this.