[m-rev.] Upgrade Boehm GC to 7.6.0

[Zoltan Somogyi]

On Tue, 20 Sep 2016 18:02:16 +1000 (AEST), Julien Fischer <jfischer at opturion.com> wrote:
> > I've tested this with hlc.gc, hlc.par.gc, asm_fast.gc, asm_fast.par.gc.stseg
> > on x86_64 Linux.  If anyone would like to test on other platforms that'd be
> > good, but it's also okay to test this once its on master.
> 
> Go and ahead and commit it to master.  I'll take a look at it on OS X
> and Windows after you do that.

I am afraid this broke my setup. I use Ubuntu 13.10, and it does
NOT have libtool installed, which is why I get errors such as these
(extracted from the output of make):

config.status: executing libtool commands
sed: can't read ./ltmain.sh: No such file or directory
mv: cannot stat 'libtoolT': No such file or directory
cp: cannot stat 'libtoolT': No such file or directory
chmod: cannot access 'libtool': No such file or directory
config.status: executing default commands
make[3]: Entering directory `/home/zs/ws/ws50/boehm_gc/libatomic_ops'
Making install in src
make[4]: Entering directory `/home/zs/ws/ws50/boehm_gc/libatomic_ops/src'
make  install-am
make[5]: Entering directory `/home/zs/ws/ws50/boehm_gc/libatomic_ops/src'
/bin/bash ../libtool  --tag=CC   --mode=compile /home/zs/ws/ws50/boehm_gc/../scripts/mgnuc --grade hlc.gc --no-ansi --no-check --no-mercury-stdlib-dir -DHAVE_CONFIG_H   -I../src -I../src  -fPIC -Wall -Wextra -g -O2 -MT atomic_ops.lo -MD -MP -MF .deps/atomic_ops.Tpo -c -o atomic_ops.lo atomic_ops.c
/bin/bash: ../libtool: No such file or directory

This is a bit rude, since the last part of that is boehm's autoconfiguration,
which did NOT check whether libtool was installed, but used it anyway.
This probably should be fixed upstream.

Any ideas on how to fix the problem, not just for me but also for every other
Mercury user in the same boat?

Doing apt-get install libtool does not work, since libtool is not found
in the ubuntu archive. Installing the current version of libtool from git
requires help2man, which also cannot be found in the ubuntu archive.

Zoltan.