Automake/Libtool does not create shared libraries

[Johnny Wezel]

What's needed to create shared libraries? My automake only creates 
static libraries.

This is my Makefile.am:

AM_CXXFLAGS = -g -DGC_OPERATOR_NEW_ARRAY -DGC_DEBUG
lib_LTLIBRARIES = libj.la
library_includedir = $(includedir)/libj
libj_la_SOURCES =\
       JFlAdd.cc\
       JFlAdd.h\
       JFlAnyValue.h\
       JFlArray.cc\
       JFlArray.h\
       JFlBinaryOperation.cc\
       JFlBinaryOperation.h\
       ...
I tried several versions of automake (1.4 thru 1.7); all behave the same.

Cheers
Johnny