I have done everything I possibly can to get this improvement into the official Arduino, even to the point of making a video demonstration to solicit more beta testing, since the Arduino Team believed this feature might be too risky without more testing.
My basic feeling is it's nearly impossible to contribute anything to Arduino, other than specific bug fixes. Even "patches welcome" doesn't mean contributed code will actually be used. For example:
http://code.google.com/p/arduino/issues/detail?id=550
Here's another example, where a feature was requested (by the Arduino Team), and I went to the trouble to produce a patch, and screenshots. They didn't like the syntax I chose, but indicated the feature itself was good. So after some back-and-forth to clarify what syntax would be desired, I pretty much redesigned the entire thing and submitted a second patch. It has sat unused for 1 YEAR.
http://code.google.com/p/arduino/issues/detail?id=257
I'm particularly bitter about the very substantial work I put into that redesign. The original approach tried to limit the scope of changes within Arduino. Since they haven't used it, I'm left with a larger patch set which I maintain separately for Teensyduino. Never again will I rework a patch like that.
I'm hoping that Arduino will eventually go to a make-based compilation, even if the default behavior is to recompile everything.
Bill, you know a make-based build has been brought up over and over on the developer mail list. The idea has been consistently rejected.
Given how hard it is to get any patch accepted (other than specific fixes to accepted bugs), even in cases like these where the idea was approved, even when "patches welcome" is said, obviously there's zero chance Arduino will ever use make, even if someone is foolish enough to try contributing that code.
The Teensyduino installer is my kludge to avoid completely forking Arduino. In hindsight, forking would be easier. My installer is NOT version independent. With each new Arduino version, it needs to be updated. It only works well because I put a huge amount of work into ongoing maintenance. I'm a little crazy like that....
I keep hoping Arduino will be more open. In hindsight, I regret putting so much work into sharing this compile speedup. I've easily spent 10X more time trying to get Arduino to actually use it than I did writing it in the first place!