diff --git a/SystemInformation.cxx b/SystemInformation.cxx
index 720a7c3b0..65440989a 100644
--- a/SystemInformation.cxx
+++ b/SystemInformation.cxx
@@ -88,15 +88,6 @@ typedef int siginfo_t;
 #  include <ifaddrs.h>
 #  define KWSYS_SYSTEMINFORMATION_IMPLEMENT_FQDN
 # endif
-# if defined(KWSYS_SYSTEMINFORMATION_HAS_BACKTRACE)
-#  include <execinfo.h>
-#  if defined(KWSYS_SYSTEMINFORMATION_HAS_CPP_DEMANGLE)
-#    include <cxxabi.h>
-#  endif
-#  if defined(KWSYS_SYSTEMINFORMATION_HAS_SYMBOL_LOOKUP)
-#    include <dlfcn.h>
-#  endif
-# endif
 #endif
 
 #if defined(__OpenBSD__) || defined(__NetBSD__)
@@ -126,16 +117,8 @@ typedef int siginfo_t;
 #  include <ifaddrs.h>
 #  define KWSYS_SYSTEMINFORMATION_IMPLEMENT_FQDN
 # endif
-# if __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__-0 >= 1050
-#  if defined(KWSYS_SYSTEMINFORMATION_HAS_BACKTRACE)
-#   include <execinfo.h>
-#   if defined(KWSYS_SYSTEMINFORMATION_HAS_CPP_DEMANGLE)
-#     include <cxxabi.h>
-#   endif
-#   if defined(KWSYS_SYSTEMINFORMATION_HAS_SYMBOL_LOOKUP)
-#     include <dlfcn.h>
-#   endif
-#  endif
+# if !(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__-0 >= 1050)
+#  undef KWSYS_SYSTEMINFORMATION_HAS_BACKTRACE
 # endif
 #endif
 
@@ -150,15 +133,6 @@ typedef int siginfo_t;
 #   define KWSYS_SYSTEMINFORMATION_IMPLEMENT_FQDN
 #  endif
 # endif
-# if defined(KWSYS_SYSTEMINFORMATION_HAS_BACKTRACE)
-#  include <execinfo.h>
-#  if defined(KWSYS_SYSTEMINFORMATION_HAS_CPP_DEMANGLE)
-#    include <cxxabi.h>
-#  endif
-#  if defined(KWSYS_SYSTEMINFORMATION_HAS_SYMBOL_LOOKUP)
-#    include <dlfcn.h>
-#  endif
-# endif
 # if defined(KWSYS_CXX_HAS_RLIMIT64)
 typedef struct rlimit64 ResourceLimitType;
 #  define GetResourceLimit getrlimit64
@@ -178,6 +152,19 @@ typedef struct rlimit ResourceLimitType;
 # include <OS.h>
 #endif
 
+#if defined(KWSYS_SYSTEMINFORMATION_HAS_BACKTRACE)
+# include <execinfo.h>
+# if defined(KWSYS_SYSTEMINFORMATION_HAS_CPP_DEMANGLE)
+#  include <cxxabi.h>
+# endif
+# if defined(KWSYS_SYSTEMINFORMATION_HAS_SYMBOL_LOOKUP)
+#  include <dlfcn.h>
+# endif
+#else
+# undef KWSYS_SYSTEMINFORMATION_HAS_CPP_DEMANGLE
+# undef KWSYS_SYSTEMINFORMATION_HAS_SYMBOL_LOOKUP
+#endif
+
 #include <memory.h>
 #include <stdlib.h>
 #include <stdio.h>
diff --git a/hashtable.hxx.in b/hashtable.hxx.in
index 62aa3f323..b93e9be6b 100644
--- a/hashtable.hxx.in
+++ b/hashtable.hxx.in
@@ -310,6 +310,9 @@ struct _Hashtable_node
 {
   _Hashtable_node* _M_next;
   _Val _M_val;
+  void public_method_to_quiet_warning_about_all_methods_private();
+private:
+  void operator=(_Hashtable_node<_Val> const&); // poison node assignment
 };
 
 template <class _Val, class _Key, class _HashFcn,