Why do some module call have a 'minus' sign in front in the config file ?

[Phil Mayers]

On 18/02/16 11:24, Sylvain Munaut wrote:
> Hi,
>
>
> Some of the modules sometimes have a "minus" (-) sign in front of them
> in config files like -sql  -ldap
>
> What purpose does it serve ?

It'll be skipped if it's not defined, IIRC.

It lets the default config be completely generic, with placeholder 
modules in the right place, but people don't have to remember to 
uncomment it.

At least, that's my recollection.