Avoiding or speeding up full tree recompilations

[John W. Eaton]

On 13-Dec-2010, Jordi Gutiérrez Hermoso wrote:

| Whenever someone touches any build files, I think, a full tree
| recompilation ensues. E.g. touching foo.mk in order to add some bar.m
| seems to trigger this.
| 
| In the interest of economising CPU cycles and slowing down the heat
| death of the universe, can this be helped? Perhaps ccache could be
| used in order to avoid recompiling at least a few things regularly
| while working with the development sources.
| 
| I ask because I don't know if it can be avoided. I've had a few
| half-hearted attempts to understand Octave's build process, and maybe
| I should try again, but I'd rather ask you people first.

If you think that the dependency information is incorrect, then submit
a patch to fix the problem or a bug report with enough specific
information that someone else can reproduce the problem you are seeing.

jwe