build erros with multiarch changes in 12.04

[Josh Stratton]

I can't possibly be the only one using qmake, right?  If I look at the
QT_INSTALL_LIBS qmake defaults to, it excludes more than half of
libraries on the system.  I know there was some discussion getting
cmake configured to use both lib directories.  Is it working for
everyone with qmake?

$ qmake -query
QT_INSTALL_PREFIX:/usr
QT_INSTALL_DATA:/usr/share/qt4
QT_INSTALL_DOCS:/usr/share/qt4/doc
QT_INSTALL_HEADERS:/usr/include/qt4
QT_INSTALL_LIBS:/usr/lib/i386-linux-gnu
QT_INSTALL_BINS:/usr/bin
QT_INSTALL_PLUGINS:/usr/lib/i386-linux-gnu/qt4/plugins
QT_INSTALL_IMPORTS:/usr/lib/qt4/imports
QT_INSTALL_TRANSLATIONS:/usr/share/qt4/translations
QT_INSTALL_CONFIGURATION:/etc/xdg
QT_INSTALL_EXAMPLES:/usr/lib/qt4/examples
QT_INSTALL_DEMOS:/usr/lib/qt4/demos
QMAKE_MKSPECS:/usr/share/qt4/mkspecs
QMAKE_VERSION:2.01a
QT_VERSION:4.8.1

On Tue, May 15, 2012 at 9:25 AM, Josh Stratton <strattonbrazil at gmail.com> wrote:
> I recently upgraded to 12.04 and noticed that apparently do to the new
> multiarch changes, there are now two lib directories on my machine:
> /usr/lib and /usr/lib/i386-linux-gnu.  When trying to compile an app I
> had been working on using qmake, it no longer picks up several of the
> libraries in /usr/lib since qmake now pulls from
> /usr/lib/i386-linux-gnu.  I have 1400 library files in the former and
> 1100 in the latter.  When do I pull from one or the other?
>
> I know the basic idea of why Ubuntu decided to do this, but I'm more
> curious as to what they expect people to do about it since now a lot
> of builds out there besides mine, I'm assuming, are going to break
> because they only pull from one library path.  In my case when I run
> qmake, I have a -L/usr/lib/i386-linux-gnu (same path I see when I run
> qmake --version) and it ignores all the files in /usr/lib like
> libassimp.so.
>
> I can link this library file (and any others I come across) into
> /usr/lib/i386-linux-gnu or hardcode /usr/lib into my qmake builds,
> which I didn't have to do before.  I'm just wondering how other Ubuntu
> users are dealing with this as it seems almost every build
> configuration I usually download assumes one library path.  What does
> Ubuntu expect developers to do in this case to elegantly handle both
> directories?
>
> Thanks, Josh