Indentation and gc

[Ergus]

Hi:

Just today I enabled the garbage-collection-messages and I found that
indenting the buffer with `C-x h <tab>` in just ~150 C++ lines I get the
garbage-collection message printed about 4 or 5 times before the
indentation finishes.

So, two questions:

1) Is this intended? if so, what's the reason? the indentation code is
forcing gc or is it generating too much garbage?

2) IF it doesn't impact performance... Is it possible somehow to improve
the gc message to have more useful information; or at least; to control
the no-log in order to have some outputs in the *Message* buffer?

Best,
Ergus