[cairo] Cairo 1.9.2 performance

[Dominic Lachowicz]

> Incidentally, I also found that default Makefiles as created by
> configure for cairo do not include any optimization options (i.e.
> CXXFLAGS contains -O3 but this does not propagate into the actual
> compile options). Adding -O3 to compile options for 1.8.6 increased
> cairo drawing speed by about 30% (260ms vs 450ms for the same dataset,
> nice :) ). I don't know if this is by design - but perhaps it is worth
> making -O3 the default build option.

The typical way to do this is to specify different CFLAGS to configure. Eg.

CFLAGS="-O3" ./configure --prefix=/opt