Fixed 3 "make check" failures on glibc 32bit built by gcc 5.0 due to EBX
was enabled for allocation:
https://gcc.gnu.org/ml/gcc-patches/2014-10/msg00892.html
Tests elf/tst-tls3, elf/tst-execstack-needed, elf/tst-execstack-prog
were failed because EBX was used as PIC register.
* sysdeps/i386/tls-macros.h: Include <features.h>.
(TLS_LE): Use non-PIC version for GCC >= 5.0.
(TLS_IE): Likewise.
(TLS_LD): Likewise.
(TLS_GD): Likewise.
* sysdeps/unix/sysv/linux/i386/sysdep.h (check_consistency): Don't
define for GCC >= 5.0.
