Description of problem:

On x86_64 machine:
$ rpmbuild --rebuild gnumeric-1.4.2-2.src.rpm
.......
.... -lxml2 -lpthread -lz -lglib-2.0 /usr/lib/libpopt.so -lm
/usr/lib/libpopt.so: could not read symbols: File in wrong format
collect2: ld returned 1 exit status

According to
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=138742#c22
the problem lies between gnumeric source tarball and gnumeric.spec
which fails to do

libtoolize --force --copy && aclocal && autoconf

Indeed, replacing in a spec file just 'autoconf' with the line
above generates link command which look for libraries in the
right places and everything recompiles.

It is true that one gets these:

acinclude.m4:17: warning: underquoted definition of AM_PATH_PROG_WITH_TEST
  run info '(automake)Extending aclocal'
  or see
http://sources.redhat.com/automake/automake.html#Extending-aclocal
acinclude.m4:67: warning: underquoted definition of AM_LC_MESSAGES
acinclude.m4:92: warning: underquoted definition of AM_WITH_NLS
acinclude.m4:270: warning: underquoted definition of AM_GNU_GETTEXT
/usr/share/aclocal/libole2.m4:18: warning: underquoted definition of
AM_PATH_LIBOLE2

but that too is not so difficult to correct.

It seems that the problem is really much wider but I run into it
in a specific case of gnumeric.

Version-Release number of selected component (if applicable):
The above is using gnumeric-1.4.2-2 but AFAIK all earlier versions
are affected the same way and sources from FC3 too.