using AM_CXXFLAGS

[Ted Irons]

Am running  autoconf-2.52, automake-1.5,  and libtool-1.4b
on a Linux box (with a 2.2 kernel).

I'm trying to figure out how to use AM_CXXFLAGS; why
shouldn't the following  work?

Thanks in advance,
- Ted

PS. Is there a FAQ somewhere?  No doubt this question
has already come up.


Snippet from Makefile.am:
-------------------

if ENABLE_KHOROS
K_CXXFLAGS = @KHOROS_CXXFLAGS@
else
K_CXXFLAGS =
endif

AM_CXXFLAGS = -I$(top_srcdir)/src  \
              $(K_CXXFLAGS)

if USING_LINUX
AM_CXXFLAGS = -DLINUX @AM_CXXFLAGS@
endif

if USING_SUNOS
AM_CXXFLAGS = -DSunOS @AM_CXXFLAGS@
endif

Here is the error I get:
----------------
src/Util/Makefile.am:16: AM_CXXFLAGS was already defined in condition TRUE, 
which implies condition USING_LINUX_TRUE

  AM_CXXFLAGS (User, where = 16) =
  {
    TRUE => -I$(top_srcdir)/src  \
              $(K_CXXFLAGS)

  }
src/Util/Makefile.am:16: AM_CXXFLAGS was already defined in condition TRUE, 
which implies condition USING_SUNOS_TRUE

  AM_CXXFLAGS (User, where = 16) =
  {
    TRUE => -I$(top_srcdir)/src  \
              $(K_CXXFLAGS)

    USING_LINUX_TRUE => -DLINUX @AM_CXXFLAGS@
  }
WARNING: `automake' is missing on your system.  You should only need it if
         you modified `Makefile.am', `acinclude.m4' or `configure.in'.
         You might want to install the `Automake' and `Perl' packages.
         Grab them from any GNU archive site.


Checking for automake:
------------------
[292.vega.Util] which automake
/swl/autoconf-2.52/Linux-2.2/bin/automake