$prefix defaults to NONE?

[Rob van der Leek]

Hi list,

I want to define a path to a configuration file in `config.h`, therefore
I call AC_DEFINE_UNQUOTED(CONFIG_FILE, $prefix/etc/config.xml, [Path to
config file])
The problem is that $prefix defaults to NONE when no --prefix flag is
given at the command line, which forces me to test for this situation
and set $prefix to '/usr/local' by hand.

Am I missing a point here? Any comments are welcome.

TIA, rob.