patch for acinclude.m4.in: Better test for "Qt without flags"

[Allan Sandfeld Jensen]

On Monday 04 August 2003 14:21, Michael Ritzert wrote:
> Hi all,
>
> I just found this problem with KDE's configure: I'm using debian unstable
> as my build system with Qt 3.1.1 installed. In another directory
> (/3/KDE/qt) I have installed qt-copy and this is what I intended to use for
> compiling KDE. Just that this attempt failed with missing symbols from
> libqt-mt.so. I traced down the problem to the following fact: KDE searches
> for Qt respecting the hints given by the user and correctly reports that it
> found everything: "result: libraries /3/KDE/qt/lib, headers
> /3/KDE/qt/include using -mt". Next it checks "if Qt compiles without
> flags". This also works. However in my case the linker it picked up the
> wrong systemwide libqt-mt.so. configure then thought everything was alright
> and created the Makefile without the -L/3/KDE/qt which explains the error I
> got.
>
> To prevent this kind of error in the future I propose the attached patch to
> have configure check whether the correct libqt-mt.so was picked up. This
> patch is mainly intended as food for thought as I have no idea how portable
> the shell code is. I checked that it work correctly for bash on GNU/Linux
> in both possible cases (wrong/correct lib linked in).
>
Another idea could be to test build-key and/or version, but I havent found out 
how to extract the build-key from the library on run-time.

`Allan