Why does one shared library cause the project to fail: Warning: Linking the executable x against the loadable module

[Yuri]

This project (calf studio) fails to build for me. Here is the 
Makefile.am that seems to cause a problem: 
https://github.com/calf-studio-gear/calf/blob/master/src/Makefile.am

It builds the shared library calf.so. The library is built, but later it 
fails when this shared library is fed to another command line as a source:

*** Warning: Linking the executable calfbenchmark against the loadable 
module
*** calf.so is not portable!


The command that creates calf.so:

libtool: link: c++  -fPIC -DPIC -shared -nostdlib /usr/lib/crti.o 
/usr/lib/crtbeginS.o  .libs/audio_fx.o .libs/analyzer.o .libs/lv2wrap.o 
.libs/metadata.o .libs/modules_tools.o .libs/modules_delay.o 
.libs/modules_comp.o .libs/modules_limit.o .libs/modules_dist.o 
.libs/modules_filter.o .libs/modules_mod.o .libs/modules_pitch.o 
.libs/fluidsynth.o .libs/giface.o .libs/monosynth.o .libs/organ.o 
.libs/osctl.o .libs/plugin.o .libs/preset.o .libs/synth.o .libs/utils.o 
.libs/wavetable.o .libs/modmatrix.o   -lexpat -L/usr/local/lib 
-lfluidsynth -lgthread-2.0 -lglib-2.0 -lintl -L/usr/lib -lc++ -lm -lc 
-lgcc -lgcc_s /usr/lib/crtendS.o /usr/lib/crtn.o  -pthread -pthread -O2 
-fstack-protector -fstack-protector -pthread   -pthread -Wl,-soname 
-Wl,calf.so -Wl,-version-script -Wl,.libs/calf.so-ver -o .libs/calf.so


Later failing command:

/bin/sh ../libtool  --tag=CXX   --mode=link c++ -ffast-math 
-finline-limit=80 -I/usr/local/include  -I/usr/local/include 
-I/usr/local/include/gtk-2.0 -I/usr/local/include/pango-1.0 
-I/usr/local/include/glib-2.0 -I/usr/local/lib/glib-2.0/include 
-I/usr/local/include -I/usr/local/include/cairo 
-I/usr/local/include/pixman-1 -I/usr/local/include/freetype2 
-I/usr/local/include/libdrm -I/usr/local/include/libpng16 
-I/usr/local/include/harfbuzz -I/usr/local/include/gdk-pixbuf-2.0 
-I/usr/local/include/atk-1.0 -D_THREAD_SAFE -pthread 
-I/usr/local/include  -I/usr/local/include/lash-1.0 
-I/usr/local/include/glib-2.0 -I/usr/local/lib/glib-2.0/include 
-I/usr/local/include -pthread  -O2 -pipe -fno-omit-frame-pointer 
-fstack-protector -fno-strict-aliasing -fno-omit-frame-pointer 
-std=c++11 -Wall  -L/usr/local/lib -fstack-protector -o calfmakerdf 
makerdf.o calf.la

*** Warning: Linking the executable calfmakerdf against the loadable module
*** calf.so is not portable!


What is wrong with this library?


Yuri