x86_64 is used as a baseline: the "x86_64" entry, whatever status it has,
is transformed into "all", and then the other entries in ARCHITECTURES
either dropped or rearranged appropriately.
openjdk7:
to simplify the recipe changes it's actually a 1.8 JDK for x86_64.
openjdk8:
* config.guess is patched to recognize haiku-x86_64.
* honor the jobs parameter.