Re: Qt5 issues in LXQt from wip

["Kamil Rytarowski" <n54%gmx.com@localhost>]

Niclas Rosenvik wrote:
> On Mon, 20 Apr 2015 00:04:45 +0200
> "Kamil Rytarowski" <n54%gmx.com@localhost> wrote:
> 
> > Regarding PIE, what's your platform?
> > I read that qt5 sources compiled with `-reduce-relocations' require
> > `-fPIE'.
> > 
> > #if !defined(QT_BOOTSTRAPPED) && defined(QT_REDUCE_RELOCATIONS) &&
> > defined(__ELF__) && !defined(__PIC__) && !defined(__PIE__) #  error
> > "You must build your code with position independent code if Qt was
> > built with -reduce-relocations. "\ "Compile your code with -fPIC or
> > -fPIE." #endif
> > 
> > -- from ${PREFIX}/qt5/include/QtCore/qglobal.h
> 
> My platform is NetBSD 6.1.5 with native gcc (4.5.3).
> And yes, your observation is correct. The problem is that PIE is only to
> be used by executables[1]. In some cases(liblxqt, lxqt-config) PIE is to
> build the objects that are included in the shared libraries and it
> leads to error messages like this:
> Linking CXX shared library liblxqt.so
> ld: CMakeFiles/lxqt.dir/lxqtplugininfo.cpp.o: relocation R_X86_64_PC32
> against symbol `_ZN4LxQt10PluginInfo4loadERK7QString' can not be used
> when making a shared object; recompile with -fPIC ld: final link
> failed: Bad value
> 
> When set(Qt5_EXECUTABLE_COMPILE_FLAG "-fPIE") is commented out in
> Qt5CoreConfigExtras.cmake everything works as expected,
> PIC is used for shared libraries and PIE is used for the executables.
> I think qt5 sets CMAKE_POSITION_INDEPENDENT_CODE[2] to TRUE and then
> cmake handles the rest. 
> I am considering to patch qt5-qtbase to comment out
> set(Qt5_EXECUTABLE_COMPILE_FLAG "-fPIE") to fix this
> but I wonder if this impacts other things.
> 
> Regards,
>  Niclas
> 
> 1.https://gcc.gnu.org/onlinedocs/gcc-4.8.4/gcc/Code-Gen-Options.html#index-fPIC-2392
> 2.http://www.cmake.org/cmake/help/v3.2/variable/CMAKE_POSITION_INDEPENDENT_CODE.html
> 

Thank you for your research, everything is now clear!

I'm slacking off with the qt5 libs' issues as they require more time
and build power then I currently have.