My distro is Ubuntu 14.04. I am installing Octave 4.2.1. I have a shell script doing this for me using GNU make.

Octave is in search of Qt libraries. I wish to use the Qt5 5.8 binaries installed from https://www.qt.io/download-open-source/ into my /opt/qt directories. The location of these qt binaries, libraries and pkgconfig are in the respective environment variables PATH, LD_CONFIG_PATH and PKG_CONFIG_PATH.

This is the excerpt of the stdout of the Octave configure regarding the Qt-related environment variables:

Qt CPPFLAGS: -I/opt/qt/5.8/gcc_64/include/QtCore -I/opt/qt/5.8/gcc_64/include -I/opt/qt/5.8/gcc_64/include/QtGui -I/opt/qt/5.8/gcc_64/include/QtNetwork -I/opt/qt/5.8/gcc_64/include/QtOpenGL -I/opt/qt/5.8/gcc_64/include/QtWidgets -I/opt/qt/5.8/gcc_64/include/QtPrintSupport  
Qt LDFLAGS: -L/opt/qt/5.8/gcc_64/lib  
Qt libraries: -lQt5Network -lQt5OpenGL -lQt5PrintSupport -lQt5Widgets -lQt5Gui -lQt5Core  

The configure fails because Qt cannot find the Qscintilla libraries in the standard location. This is fair, because these files are in /usr/include/qt5/Qsci, which is associated with the qt5 installed with the package management tool (that I would sidestep).

I wanted to add the path to that QScintilla during configuration. From less ${srcdir}/configure.ac | grep QT I trace back that the environment variable to be edited is QT_CPPFLAGS, probably.


Whether I do

export QT_CPPFLAGS="-I/usr/include/qt5/Qsci ${QT_CPPFLAGS}"
${srcdir}/configure  # other switches omitted


${srcdir}/configure  QT_CPPFLAGS="-I/usr/include/qt5/Qsci ${QT_CPPFLAGS}"

I do not manage to add my path to the existing ones. The configure log shows the same locations in /opt/qt/5.8/ and no more.


How can I actually append an item to the list of the include directories?

Do you spot any flaws?

  • You're supposed to use qmake instead – daisy Mar 5 '17 at 16:51
  • @daisy Can you please provided an extended explanation as a candidate answer? Thanks in advance – XavierStuvw Mar 5 '17 at 18:49

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