[Debian-med-packaging] Bug#813436: iqtree: FTBFS on most 32-bit platforms: -m32 -msse3 inappropriate

[Aaron M. Ucko]

Source: iqtree
Version: 1.3.11.1+dfsg-1
Severity: important
Justification: fails to build from source

Builds of iqtree on most 32-bit platforms failed with errors related
to the use of -m32, -msse3, or both.  Neither option yielded build
errors on *i386, which failed due to a different problem I'll report
shortly.  x32 also supports both flags, but interprets -m32 as
requesting an i386 build, for which a suitable libstdc++ development
package was absent:

  /usr/include/c++/5/new:39:28: fatal error: bits/c++config.h: No such file or directory
  compilation terminated.

The remaining architectures failed with errors of the form

  cd /«BUILDDIR»/iqtree-1.3.11.1+dfsg/obj-arm-linux-gnueabi/model && /usr/bin/c++   -DBINARY32 -DIQ_TREE -D_USE_PTHREADS -D__SSE3 -I/«BUILDDIR»/iqtree-1.3.11.1+dfsg -I/«BUILDDIR»/iqtree-1.3.11.1+dfsg/obj-arm-linux-gnueabi -I/usr/include/eigen3  -g -O2 -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2  -fopenmp  -m32   -msse3 -o CMakeFiles/model.dir/modelgtr.cpp.o -c /«BUILDDIR»/iqtree-1.3.11.1+dfsg/model/modelgtr.cpp
  c++: error: unrecognized command line option '-m32'
  c++: error: unrecognized command line option '-msse3'
  model/CMakeFiles/model.dir/build.make:65: recipe for target 'model/CMakeFiles/model.dir/modelgtr.cpp.o' failed

though some at least supported -m32 as a no-op.

It is generally inappropriate to use either option when building
Debian packages on any architecture; the compiler already defaults to
the right overall ABI, and specifying flags like -msse3 normally
limits the portability of the resulting binaries (unless code relying
on the extension is carefully predicated on a CPUID test).

Could you please take a look?

Thanks!