Add ChangeLog entry for r197770 (in boehm-gc).

From-SVN: r198562

boehm-gc/ChangeLog

+2013-03-16  Yvan Roux <yvan.roux@linaro.org>
+
+        * include/private/gcconfig.h (AARCH64): New macro (defined only if
+        __aarch64__).
+        (CPP_WORDSZ): Define for AArch64.
+        (MACH_TYPE): Likewise.
+        (ALIGNMENT): Likewise.
+        (HBLKSIZE): Likewise.
+        (OS_TYPE): Likewise.
+        (LINUX_STACKBOTTOM): Likewise.
+        (USE_GENERIC_PUSH_REGS): Likewise.
+        (DYNAMIC_LOADING): Likewise.
+        (DATASTART): Likewise.
+        (DATAEND): Likewise.
+        (STACKBOTTOM): Likewise.
+        (NOSYS): Likewise.
+        (mach_type_known): Define for AArch64 and comment update.
+
 2013-03-06  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>
 
 	* os_dep.c [SOLARIS_STACKBOTTOM] (GC_solaris_stack_base): New