Configuring the makefile

[Kostantino]

Hi.
In the INSTALL file I read:
--enable-optimization=VALUE enables you to set optimization
  to a higher level as the default (-O), for example
--enable-optimization=-O3.
So I give the following configure command:

./configure --with-frontend=qt --enable-optimization=-O3

but after the make command I read:

        g++: unrecognised option '-03'

This behaviour still remains if I give before the command:

         CXXFLAGS='-03'

for BASH.

I use Linux-2.4.22 on Slackware 9.1, LyX-1.3.3, gcc (GCC) 3.2.3,
g++ (GCC) 3.2.3
Any suggestions for me? Perhaps I wrong something?
        best regards

Costantino