comptools: do not force build of make-3.81 unless really needed

On systems with make-3.82, we forcibly force the build and the use
of make-3.81

But some newer tools break when building with make-3.81. For example,
eglibc-3.18 breaks.

Introduce a new blind options that tools may select if they require
make-3.81. If the system does not have make-3.81, and this option is
selected, then we force the build of make-3.81. Otherwise, we leave
it to the user to decide on his own.

Note that no component selects this option for now. It will come in
later patches as we find them.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

2008-04-28  Hiroki Kaminaga  <kaminaga@sm.sony.co.jp>

	[BZ 6740]

	nptl/sysdeps/powerpc/tcb-offsets.sym (PRIVATE_FUTEX_OFFSET):

	Guard sym definition with #ifndef __ASSUME_PRIVATE_FUTEX.

--- a/nptl/sysdeps/powerpc/tcb-offsets.sym

+++ b/nptl/sysdeps/powerpc/tcb-offsets.sym

@@ -15,4 +15,6 @@

 PID				thread_offsetof (pid)

 TID				thread_offsetof (tid)

 POINTER_GUARD			(offsetof (tcbhead_t, pointer_guard) - TLS_TCB_OFFSET - sizeof (tcbhead_t))

+#ifndef __ASSUME_PRIVATE_FUTEX

 PRIVATE_FUTEX_OFFSET		thread_offsetof (header.private_futex)

+#endif