Fix ADD_DEFINITION in CMakeLists.txt for kFreeBSD

* CMakeLists.txt: Fix broken ADD_DEFINITION for kFreeBSD.
Fix CMakeLists.txt: do not override CMAKE_OSX_ARCHITECTURES

* CMakeLists.txt: Since latest OSX compiler (clang) provided by Xcode is
not accept "-arch ppc"; So if CMAKE_OSX_ARCHITECTURES is defined by
client, CMakeLists.txt should not force "ppc;i386;x86_64".
Fix typo in GC_collect_or_expand comment

* alloc.c (GC_collect_or_expand): Fix a typo in comment ("setting").
Bump GC_collect_at_heapsize in GC_add_to_heap. In the normal case it is
recalculated straight after. But in the case where it's called directly
from alloc_mark_stack, it isn't. If the mark stack gets very large,
this can cause GC_should_collect to always return true, and
GC_alloc_large to get stuck in a loop calling GC_collect_or_expand.
(Apply commit 5f8f104 from 'release-7_4' branch.)

Conflicts:

    alloc.c
Fix mark stack excessive growth during parallel mark
(The growth observed in applications that implement things like weak
hash tables and iterate over the members marking entries using the
supplied GC_MARK_AND_PUSH macro.)
(Apply commit 811b3eb from 'release-7_4' branch.)

When overflow is signaled, only set GC_mark_stack_too_small if we
are using the global mark stack.  In parallel mode, local mark stack
is used, so the global mark stack is grown by GC_return_mark_stack
mainly.

* mark.c (GC_signal_mark_stack_overflow): Do not set
GC_mark_stack_too_small if GC_parallel.

Conflicts:

    mark.c
Fix typo in GC overview file

* doc/overview.html: Fix a typo ("See").
Fix or remove broken URLs in documentation
(Apply commit e4559d3 from 'release-7_4' branch.)

* doc/README.cords: Remove broken link to reality.sgi.com.
* doc/README.environment: Fix link to HPL tech reports.
* doc/overview.html: Remove broken link to parcftp.xerox.com.
* doc/overview.html: Fix (or update) external links.

Conflicts:

    doc/overview.html
Update emails/links due to project site and ML transition
(www.hpl.hp.com/personal/Hans_Boehm -> www.hboehm.info;
gc@linux.hpl.hp.com -> bdwgc@lists.opendylan.org)
(Apply commit 64ad6f0 from 'release-7_4' branch.)

* doc/gc.man: Update email.
* doc/README.cords: Likewise.
* README.QUICK: Change external link to gcinterface.html to local one
(pointing to the file in "doc" folder).
* doc/README: Replace BDWGC site URL (www.hpl.hp.com/personal/Hans_Boehm
to www.hboehm.info).
* doc/gc.man: Likewise.
* doc/gcdescr.html: Likewise.
* doc/gcinterface.html: Likewise.
* doc/overview.html: Likewise.
* doc/scale.html: Likewise.
* doc/README: Update mailing list info (gc@linux.hpl.hp.com to
bdwgc@lists.opendylan.org, gc-announce@linux.hpl.hp.com to
bdwgc-announce@lists.opendylan.org).
* configure.ac: Likewise.
* doc/gcdescr.html: Likewise.
* doc/overview.html: Likewise.
* doc/tree.html: Remove unnecessary external link.

Conflicts:

    AUTHORS
    README.QUICK
    configure.ac
    doc/README
    doc/overview.html
Fix GET_MEM argument rounding in GC_scratch_alloc and similar
(Prevent abort in GC_unix_mmap_get_mem if the allocation size is not
a multiple of a page size.)
(Apply commit 62bfeb0 from 'release-7_4' branch.)

* backgraph.c (new_back_edges, push_in_progress): Use
ROUNDUP_PAGESIZE_IF_MMAP() to adjust GET_MEM() argument (when needed).
* headers.c (GC_scratch_alloc): Likewise.
* misc.c (GC_envfile_init): Likewise.
* include/private/gc_priv.h (ROUNDUP_PAGESIZE_IF_MMAP): New macro.
* include/private/gcconfig.h (MMAP_SUPPORTED): Move definition from
os_dep.c (as needed for ROUNDUP_PAGESIZE_IF_MMAP() definition).
* include/private/gcconfig.h (GET_MEM): Refine comment (regarding its
argument).

Conflicts:

    include/private/gcconfig.h
    os_dep.c
Fix out-of-memory case in new_back_edges, push_in_progress (backgraph)

* backgraph.c (new_back_edges): Abort if not enough memory.
* backgraph.c (push_in_progress): Prevent null pointer dereference in
BCOPY() if allocation failed (due to not enough memory).
Fix GC_scratch_last_end_ptr update on GC_scratch_alloc failure

* headers.c (GC_scratch_alloc): Do not update GC_scratch_last_end_ptr
if allocation failed ("result" variable is NULL).
Fix a typo in gc_config_macros.h comment (redundant "an" article)

* include/gc_config_macros.h (GC_ADD_CALLER): Fix a typo in comment
(redundant "an" article).
Fix build (broken by fenv.h inclusion) on Linux/x86_64 under uClibc
(Apply commit 295f454 from 'release-7_4' branch.)

* include/private/gcconfig.h (GETCONTEXT_FPU_EXCMASK_BUG): Do not
define for uClibc, as it may not have fenv.h.

Conflicts:

    include/private/gcconfig.h
Fix typos in names in README.changes file
(Apply commit caf301b from 'release-7_4' branch.)

* README.changes: Fix typo in surname (Bryce McKinlay, Slava Sysoltsev).
* README.changes: Fix typo in name or surname (Philip Brown,
Rutger Ovidius).
* README.changes: Place surname after 1st name (Tommaso Tagliapietra).

Conflicts:

    AUTHORS
    ChangeLog
Update Xerox FTP host name in overview.html

* doc/overview.html: Update FTP host name (ftp.parc.xerox.com).
Fix typo in person name in gc_cpp.h comment

* include/gc_cpp.h: Fix typo in surname (John Ellis) in comment.
Fix typos in README.changes (in items for ancient GC releases)
(Apply commit 1d5c8d5 from 'release-7_4' branch.)

* README.changes: Fix typos ("nonexistent", "to", "posting", "bit rot",
"likely", "flaky").
* README.changes: Fix typos in surname (Juan Jose Garcia-Ripoll,
Paolo Molaro, Andreas Tobler).
* README.changes: Fix incorrect article ("a finalizable").

Conflicts:

    ChangeLog
Update (regenerate) configure files; update ChangeLog

* configure: Regenerate.