Compiler warnings in R10B

[Bjorn Gustavsson]

We will change default warning behaviour in the Erlang
compiler in R10B like this:

When using 'erlc', by default warnings will be turned on.
To disable all warnings, use the '-W0' flag. To turn on
maximum warnings, use '-Wall'.

When using either 'erlc' or the Erlang compiler from the
shell, by default 'warn_unused_vars' is turned on.
(Use 'nowarn_unused_vars' to turn it off.)

We will probably also introuduce an option to turn warnings
to errors. At the same, we will look at how certains warning
can be turned off. For instance, if you deliberately name
a function 'size/1' in a module, it should be possible to turn
off the warning that you are re-defining a BIF.
  
/Bjorn

-- 
/Björn Gustavsson, Erlang/OTP, Ericsson AB