Update memcheck.supp to suppress a valgrind warning caused by a bug in tcmalloc-2.0

src/memcheck.supp

@@ -75,3 +75,30 @@
    fun:reader_loop
    fun:main
 }
+
+{
+   # This entry suppresses the warning caused by a bug in tcmalloc-2.0.
+   # Using tcmalloc-2.1 solves this problem. 
+   TCMalloc_2.0_Bug
+   Memcheck:Param
+   msync(start)
+   fun:__msync_nocancel
+   obj:*/libunwind.so.8.0.0
+   obj:*/libunwind.so.8.0.0
+   obj:*/libunwind.so.8.0.0
+   obj:*/libunwind.so.8.0.0
+   fun:_UL*_step
+   fun:*GetStackTrace*
+   fun:*PageHeap*GrowHeap*
+   fun:*PageHeap*New*
+   fun:*CentralFreeList*Populate*
+   fun:*CentralFreeList*FetchFromSpansSafe*
+   fun:*CentralFreeList11RemoveRange*
+   fun:*ThreadCache*FetchFromCentralCache*
+   fun:malloc
+   fun:*TCMallocGuard*
+   obj:*/libtcmalloc.so.*
+   fun:call_init.*
+   fun:_dl_init
+   obj:*/ld-2.*
+}