Strange behaviour in libtool-1.5.20

[Пухальский Юрий Андреевич]

Good day!

I've encountered a strange behaviour on RedHat 9, with libtool 1.5.20 and gcc 
3.4.3. I think, with previous libtool releases was the same problem.
I have two files:
a.c:
---------
void a()
{
}
------------
And b.c:
------------
void b()
{
}
----------------
I have then a Makefile.am like following:
----------------
noinst_LTLIBRARIES=liba.la libb.la

libb_la_SOURCES=b.c

liba_la_SOURCES=a.c
liba_la_LIBADD=libb.la
liba_la_LDFLAGS=-o la.o
----------------

Resulting object file la.o contains a.o.
When we configure it with --disable-shared, la.o doesn't contain a.o (because 
apparently it wants to put .libs/a.o into the library, and there is no such 
file). Then question is what partial linking has to do with shared libraries? 
Because I can still make a library solely of a.o like following:
-------------------
noinst_LTLIBRARIES=liba.la libb.la libc.la

libb_la_SOURCES=b.c

libc_la_SOURCES=a.c

liba_la_SOURCES=
liba_la_LIBADD=libc.la libb.la
liba_la_LDFLAGS=-o la.o
--------------
and have both a.o and b.o in resulting la.o...