.lo files

[alain . bonnefoy]

I'm trying to build php-4.3.3.
I did as for many other packages (libxml2, libxslt, libiconv, zlib, etc.....)
but it seems there is something different here concerning the way it links the
application.

configure is ok, make is ok until link process. the command is:

#> libtool --silent --preserve-dup-deps --mode=link -L/opt/lib -R /opt/lib
ext/zlib/zlib.lo ......

result is:
ext/zlib/zlib.lo is not a valid libtool object.

I checked all generated .lo files and all are 1 byte long! In the same directory
of each lo file, there is normal .o file.

What are these lo files?
How to fix the problem?

Thanks,
Alain.