ports/155949: www/firefox: firefox 4, WITH_PGO, better Text against DISPLAY problem

[Bernhard Froehlich]

I think the cleanest solution would be a check before starting build to
detect if X is available or not. (ideally configure or otherwise port
Makefile) But if we are talking about PGO removal do we have some
numbers how much speed you gain? I don't feel any differences on my
machine and JS benchmarks are about the same. Mozilla ships his own
Firefox binaries all without PGO so I'm not sure about the support of
that optimizations.

Drawbacks:
1) 2 full compiler runs - build time about ~2.5x
2) requires X to actually run the binary and do some profiling
3) it tends to fail in some cases

-- 
Bernhard Froehlich
http://www.bluelife.at/