bug#12242: Emacs 24.2 RC1 build fails on OpenBSD

[YAMAMOTO Mitsuharu]

>>>>> On Wed, 22 Aug 2012 19:58:12 +0300, Eli Zaretskii <eliz@gnu.org> said:

>>> My reading of the code is that inhibiting relocation just means
>>> that ralloc.c always asks for more memory when it cannot find a
>>> large enough block in the existing heaps.
>> 
>> For example, `virtual_break_value' is not updated in that case.  It
>> can lead to an inconsistent state as reported if r_alloc_sbrk is
>> called with a positive argument via malloc when
>> use_relocatable_buffers <= 0, and then it is called with a negative
>> argument via free when use_relocatable_buffers > 0.

> I see your point.

Sorry, I noticed that the senario I gave above was actually bogus.
Typically free will call r_alloc_sbrk(0) and check the return value
with respect to the area to be reclaimed before calling r_alloc_sbrk
with a negative argument.

Now I don't have a concrete senario to conclude that it is wrong to
change use_relocatable_buffers temporarily.  I'm really sorry if my
previous posts confused you.

                                     YAMAMOTO Mitsuharu
                                mituharu@math.s.chiba-u.ac.jp