This introduces make variable NO_PTHREADS for platforms that lack the
support for pthreads library or people who do not want to use it for
whatever reason. When defined, it makes the multi-threaded index
preloading into a no-op, and also disables threaded delta searching by
pack-objects.
Signed-off-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Mike Ralphson <mike@abacus.co.uk> Tested-by: Johannes Sixt <j6t@kdbg.org> (AIX 4.3.x) Signed-off-by: Junio C Hamano <gitster@pobox.com>