On Linux when following the instructions in the
in lcl/interfaces/qt5/cbindings/README.TXT, I get this error during the make stage:

g++ -c -m64 -pipe -Wfatal-errors -g -w -D_REENTRANT -fPIC -DBINUX -DQT_PRINTSUPPORT_LIB -DQT_WIDGETS_LIB -DQT_X11EXTRAS_LIB -DQT_GUI_LIB -DQT_NETWORK_LIB -DQT_CORE_LIB -I. -isystem
/usr/include/x86_64-linux-gnu/qt5 -isystem
/usr/include/x86_64-linux-gnu/qt5/QtPrintSupport -isystem /usr/include/x86_64-linux-gnu/qt5/QtWidgets -isystem /usr/include/x86_64-linux-gnu/qt5/QtX11Extras -isystem /usr/include/x86_64-linux-gnu/qt5/QtGui -isystem
/usr/include/x86_64-linux-gnu/qt5/QtNetwork -isystem /usr/include/x86_64-linux-gnu/qt5/QtCore -Itmp
-I/usr/lib/x86_64-linux-gnu/qt5/mkspecs/linux-g++-64 -o tmp/qwindow_c.o src/qwindow_c.cpp
In file included from src/qwindow_c.cpp:12:0:
src/qwindow_c.h:54:113: error: ‘QWindow::AncestorMode’ is not a class or namespace
handle, const QWindowH child, QWindow::AncestorMode mode = QWindow::AncestorMod
^
compilation terminated due to -Wfatal-errors.
Makefile:2587: recipe for target 'tmp/qwindow_c.o' failed make: *** [tmp/qwindow_c.o] Error 1

Building on Ubuntu 16.04. Any suggestions?
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.lazarus-ide.org/pipermail/lazarus/attachments/20180319/05a5b85d/attachment.html>

Anthony Walter wrote

Building on Ubuntu 16.04. Any suggestions?

Probably you're using Qt5 lib < 5.6. AFAIR Ubuntu 16.04 have Qt-5.5 by default (same as mint 18.3), I've successfully installed Qt5 5.6.1 from some ubuntu repo and it works like a charm.

zeljko