How to reduce compile times?

[grauzone]

Jarrett Billingsley wrote:
> On Sat, Mar 21, 2009 at 3:45 PM, grauzone <none at example.net> wrote:
>> Also, I noticed that "dsss build -full" seems to be the way to pass this
>> flag on the command line. But the project is recompiled even when no file
>> was modified at all. This is not good: it should only recompile if something
>> has changed.
> 
> Why would you recompile if you haven't changed anything?  :P

I want to build system to recompile the program automatically before I 
execute it. Doing this manually is not an option, because it's annoying 
and I could forget it.