use program_prefix without passing it

[Jose Roman Bilbao]

Hi,

Can I make use of the program_prefix variable without passing it through
the ./configure call?. Basically I want a default prefix to exist.

I have tried this:

if test "$program_prefix" = NONE
then
        program_prefix="myprefix"
fi

but it does not seem to perform the substitution... May be an autoconf
internal... Can you help me to solve this?

Thanks