Log Message:
Update to 7.4.2:

== [7.4.2] 2014-06-03 ==

* Add config option to use STGRTMIN-based signals for thread suspend/resume.
* Allow parallel mark to be enabled on powerpc-linux systems.
* Check for Fujitsu compiler in builtin_unwind logic (enable FX10/K-Computer).
* Fix 'Array subscript is above array bounds' GCC warning in GC_new_kind/proc.
* Fix 'attribute declaration must precede definition' warning (clang-3.1).
* Fix (enable) Cygwin-64 build.
* Fix GC_finalized_malloc failure on disclaim_test.
* Fix GC_sig_suspend initialization when non-constant SIGRTMIN used.
* Fix MS VC redefinition warning for functions declared with GC_ATTR_MALLOC.
* Fix TEXT() usage for concatenated strings in GC_CreateLogFile (Win32).
* Fix data roots registration for Android/x86 and NDK ARM 'gold' linker.
* Fix find stackbottom on BlueGene P/Q systems.
* Fix machdep .lo files path in configure (SPARC, IA-64).
* Fix ok_init assignment (missing cast) in GC_new_kind_inner.
* Fix typos in names in AUTHORS and ChangeLog files.
* Remove barrett_diagram file duplicated by tree.html.
* Remove non-existing DISCARD_WORDS from GC data structure ASCII diagram.
* Restore contribution information for ancient releases in ChangeLog.
Also, includes 7.2f changes.