how to set a default program-prefix whithin configure.ac

[JRBCAST]

Hi all,

First of all, sorry if you have received this mail two times. 

My question is: How can I set a default progra-prefix without the need 
to explicitely pass it whith: ./configure --program-prefix ...

Another question is: Once the user sets it using ./configure --program-
prefix, which variable should I work with to make changes?.

Thanks,
Roman