Fix elf: Do not duplicate the GLIBC_TUNABLES string

commit 2a969b53
Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date:   Wed Dec 6 10:24:01 2023 -0300

    elf: Do not duplicate the GLIBC_TUNABLES string

has

@@ -38,7 +39,7 @@
    which isn't available.  */
 #define CHECK_GLIBC_IFUNC_PREFERRED_OFF(f, cpu_features, name, len) \
   _Static_assert (sizeof (#name) - 1 == len, #name " != " #len); \
-  if (memcmp (f, #name, len) == 0)             \
+  if (tunable_str_comma_strcmp_cte (&f, #name) == 0)       \
     {                           \
       cpu_features->preferred[index_arch_##name]        \
   &= ~bit_arch_##name;                \
@@ -46,12 +47,11 @@

Fix it by removing "== 0" after tunable_str_comma_strcmp_cte.