Backporting changes to the support/ subdirectory.

This is kept separate from glibc-rh1418978-1.patch to simplify rebases

of the support/ subdirectory.  Changes here should be restricted to

things that absolutely cannot be upstreamed at this point (such as

support for older compilers).

diff --git a/support/blob_repeat.c b/support/blob_repeat.c

index 16c1e448b990e386..a2d5e0cbd736f998 100644

--- a/support/blob_repeat.c

+++ b/support/blob_repeat.c

@@ -30,6 +30,9 @@

 #include <unistd.h>

 #include <wchar.h>

+/* For check_mul_overflow_size_t.  */

+#include <malloc/malloc-internal.h>

+

 /* Small allocations should use malloc directly instead of the mmap

    optimization because mappings carry a lot of overhead.  */

 static const size_t maximum_small_size = 4 * 1024 * 1024;

@@ -118,8 +121,8 @@ minimum_stride_size (size_t page_size, size_t element_size)

      common multiple, it appears only once.  Therefore, shift one

      factor.  */

   size_t multiple;

-  if (__builtin_mul_overflow (page_size >> common_zeros, element_size,

-                              &multiple))

+  if (check_mul_overflow_size_t (page_size >> common_zeros, element_size,

+                                 &multiple))

     return 0;

   return multiple;

 }

@@ -255,7 +258,7 @@ support_blob_repeat_allocate (const void *element, size_t element_size,

                               size_t count)

 {

   size_t total_size;

-  if (__builtin_mul_overflow (element_size, count, &total_size))

+  if (check_mul_overflow_size_t (element_size, count, &total_size))

     {

       errno = EOVERFLOW;

       return (struct support_blob_repeat) { 0 };

diff --git a/support/links-dso-program.cc b/support/links-dso-program.cc

index dba6976c0609a332..8ff3155dd7fcd757 100644

--- a/support/links-dso-program.cc

+++ b/support/links-dso-program.cc

@@ -1,3 +1,8 @@

+/* Change for backporting: The build system does not define _ISOMAC

+   for us because the tests-internal changes have not been

+   backported.  */

+#define _ISOMAC 1

+

 #include <iostream>

 using namespace std;