ALT_PARALLEL_COMPILE_JOBS not honoured by the hotspot subproject

[Volker Simonis]

hi,

ALT_PARALLEL_COMPILE_JOBS is currently only honoured by the corba and
the jdk subprojects while the hotspot subproject uses
HOTSPOT_BUILD_JOBS as indicator to do a parallel build.

Unfortunately, neither ALT_PARALLEL_COMPILE_JOBS nor
HOTSPOT_BUILD_JOBS is handed over from the top-level makefile to the
hotspot makefile. This can be however fixed easily by adding the
following lines to make/hotspot-rules.gmk, just before the
hotspot-build target:

ifneq ($(PARALLEL_COMPILE_JOBS), 1)
  HOTSPOT_BUILD_ARGUMENTS += HOTSPOT_BUILD_JOBS=$(PARALLEL_COMPILE_JOBS)
endif

After this change, setting ALT_PARALLEL_COMPILE_JOBS on the make
command line of the top-level makefile, will be enough to trigger a
parallel hotspot build.

Regards,
Volker