x86: Fix strstr ifunc on clang

Work around the clang limitation wrt inline function and attribute
definition, where it does not allow to 'add' new attribute if a
function is already defined:

Buildint with clang triggers multiple issue on how ifunc macro are
used:

  ../sysdeps/x86_64/multiarch/strstr.c:38:54: error: attribute declaration must precede definition [-Werror,-Wignored-attributes]
     38 | extern __typeof (__redirect_strstr) __strstr_generic attribute_hidden;
        |                                                      ^
  ./../include/libc-symbols.h:356:43: note: expanded from macro 'attribute_hidden'
    356 | # define attribute_hidden __attribute__ ((visibility ("hidden")))
        |                                           ^
  ../string/strstr.c:76:1: note: previous definition is here
     76 | STRSTR (const char *haystack, const char *needle)
        | ^
  ../sysdeps/x86_64/multiarch/strstr.c:27:16: note: expanded from macro 'STRSTR'
     27 | #define STRSTR __strstr_generic
        |                ^
  ../sysdeps/x86_64/multiarch/strstr.c:65:43: error: redefinition of '__libc_strstr'
     65 | libc_ifunc_redirected (__redirect_strstr, __libc_strstr, IFUNC_SELECTOR ());
        |                                           ^

And

  ../sysdeps/x86_64/multiarch/strstr.c:65:43: error: redefinition of '__libc_strstr'
     65 | libc_ifunc_redirected (__redirect_strstr, __libc_strstr, IFUNC_SELECTOR ());
        |                                           ^
  ../sysdeps/x86_64/multiarch/strstr.c:59:13: note: previous definition is here
     59 | libc_ifunc (__libc_strstr,
        |             ^

Refactor to use a auxiliary function like other selection (for instance,
x86_64/multiarch/strcmp.c).

0 files changed, 0 insertions, 0 deletions