Fixes for Compilation of v3.4 on Ubuntu 20.04

Good afternoon,

On Ubuntu 20.04, the latest available version appears to be 3.3.1 which suffers from the fatal "[Gtk] Fix crash in Utils::string_split_pos" error fixed in https://github.com/manisandro/gImageReader/commit/6ead57d46fce179306067fcba484bf558b5ff913.

This PR contains two fixes for compiling 3.4 into Ubuntu 20.04.

https://github.com/manisandro/gImageReader/commit/d070af4cb839d23dd235967be6fb497d4082765c fixes the following:

In file included from /home/dave/Software/gImageReader/qt/src/Displayer.cc:23:
/home/dave/Software/gImageReader/qt/src/DisplayRenderer.hh:68:14: error: ‘unique_ptr’ in namespace ‘std’ does not name a template type
   68 |         std::unique_ptr<Poppler::Document> m_document;
      |              ^~~~~~~~~~
/home/dave/Software/gImageReader/qt/src/DisplayRenderer.hh:26:1: note: ‘std::unique_ptr’ is defined in header ‘<memory>’; did you forget to ‘#include <memory>’?
   25 | #include <QMutex>
  +++ |+#include <memory>
   26 |

and https://github.com/manisandro/gImageReader/commit/76d03023f73bc8dc2837af6008939d9d248578ed fixes the multiple occurances of:


     /home/dave/Software/gImageReader/qt/src/FileTreeModel.cc: In member function ‘QModelIndex FileTreeModel::insertFile(QString, DataObject*, const QString&)’:
/home/dave/Software/gImageReader/qt/src/FileTreeModel.cc:76:86: error: ‘SkipEmptyParts’ is not a member of ‘Qt’
   76 | st path = m_root->path.mid(fileDir.length()).split("/", Qt::SkipEmptyParts);
 |                                                             ^~~~~~~~~~~~~~

Best, Dave

manisandro / gImageReader

Fixes for Compilation of v3.4 on Ubuntu 20.04 #591