Log Message:
Updated boehm-gc to 7.4.4.

== [7.4.4] 2016-05-25 ==

* Allow GC_FAST_MALLOC_GRANS() multiple use in a function.
* Also enable the TSX workaround for i386 (Linux).
* Avoid unstructured procfs on Solaris.
* Change cord/de main() declaration style from K-R to ANSI C.
* Change no-argument functions declaration style to ANSI C (cord).
* Do not include sigcontext.h and asm/sigcontext.h.
* Eliminate 'divide by zero' compiler warning in cordtest.
* Eliminate warning about 64-bit pointer-to-int cast (Win64/pthreads-w32).
* Eliminate warnings detected by Cppcheck in cord de[_win].
* Fix 'comparison of non-null parameter is always false' warning (Clang).
* Fix 'CORD_iter5 unused result' code defect in cordxtra.
* Fix 'GC_generic_malloc_inner_ignore_off_page not used' compiler warning.
* Fix 'implicit declaration of vsnprintf' GCC warning (if strict ANSI mode).
* Fix 'signed-to-bigger-unsigned value assignment' in GC_init_size_map.
* Fix 'signed-to-bigger-unsigned value assignment' warning for hb_map.
* Fix 'signed-to-bigger-unsigned value assignment' warning in GC_setpagesize.
* Fix 'statement unreachable' compiler warning in GC_mark_from.
* Fix 'statement unreachable' compiler warning in memalign.
* Fix 'unused label' compiler warning in cord/de.
* Fix 'value truncated' compiler warning in CORD_cat (MS VC).
* Fix 'variable unused' warning in GC_save_callers.
* Fix 'visibility attribute not supported' GCC warning (IBM AIX).
* Fix CMake warning about CMP0054 by unquoting instances of HOST.
* Fix Cygwin64 build.
* Fix GC_REALLOC to call GC_FREE if new size is zero and pointer is non-NULL.
* Fix Makefile.direct for Cygwin.
* Fix __alloc_size__ availability detection (Clang).
* Fix abort message in GC_move_long_link.
* Fix and code refactoring of lock elision workaround (Linux/x64).
* Fix assertion on mark_lock_holder for non-unique NUMERIC_THREAD_ID.
* Fix data race in GC_init_explicit_typing.
* Fix gc.mak regarding msvc_dbg and test (MSVC).
* Fix missing error handling of pthread_attr_init/getstacksize.
* Fix missing error handling of pthreads_mutex_init and cond_wait.
* Fix missing numeric casts in cord.
* Fix potential left shift overflows in finalize.c (64-bit targets).
* Fix pthreads-win32 name in comments and documentation.
* Fix setup_mark_lock missing prototype.
* Fix unchecked fcntl() result.
* Fix unchecked pointer dereference in check_ints (gctest).
* Fix unchecked pthread_join() result in threadkey_test.
* Fix unchecked sigdelset() result in pthread_support.
* Fix undefined PTRFREE/NORMAL in gc_inline.h.
* Prefix PREFETCH_FOR_WRITE with GC_ as used in gc_inline.h public header.
* Relax mark_mutex attribute needed to disable elision (Linux/x64).
* Remove (deprecate) TODO file.
* Remove code duplication in GC_realloc.
* Remove duplicate new-line in OUT_OF_MEMORY message (cord).
* Remove references to missing linux_threads.c from documentation.
* Revert "Move asm machine-dependent files to 'src' folder" (partly).
* Support Android API level 21.
* Update compiler options in gc.mak (Win32).
* Use mmap instead of sbrk (Hurd).
* Workaround 'comparison is always false' GCC warning in GC_FAST_MALLOC_GRANS.
* Workaround 'identical expr on both sides of bitwise op' warning.
* Workaround Linux NTPL lock elision bug.
* Workaround false warning about unreachable code path.
* Workaround invalid '_end' symbol on Android clang 3.5+.
Also, includes 7.2g changes.