[Libreoffice] gnumake / dependencies 20%+ speedup ...

[Caolán McNamara]

On Mon, 2011-09-05 at 12:38 +0100, Michael Meeks wrote:
> 	I attach an updated cleanup.pl - that leaves the dummy rules, but
> removes duplicates in them

Hmm, these dependencies and the pseudo-rules are initially spit out by
gcc's -MP so...
a) I'd have expected gcc to list each dependency only once in the first
place per .c/.cxx file anyway.
b) And then I'd have expected it to then only emit one dummy rule per
dependency for those.

Looking at 
workdir/unxlngx6/Dep/CxxObject/sc/source/filter/excel/xepage.d I see
that for path/to/CxxObject/sc/source/filter/excel/xepage.o there is
already core/sc/inc/scdllapi.h listed twice as a dependency for
sc/source/filter/excel/xepage.o and correspondingly two pseudo rules for
scdllapi.h

Each pseudo-rule I *assume* is spat out by gcc on a one-to-one basis for
each dependency. So I wonder why gcc for e.g. xepage lists scdllapi.h
twice ?

When we combine them together into the final library .d then we'd still
need dup-removal between the various constituent .d files alright.

C.