Avoid __atomic_and/or/xor_fetch if unsupported (clang/arm-v5te)

Avoid __atomic_and/or/xor_fetch if unsupported (clang/arm-v5te)

* src/atomic_ops/sysdeps/gcc/arm.h (AO_SKIPATOMIC_ANY_and_ANY,
AO_SKIPATOMIC_ANY_or_ANY, AO_SKIPATOMIC_ANY_xor_ANY): Define new
internal macro (before include "generic.h") if
AO_GCC_ATOMIC_TEST_AND_SET and __clang__, and not AO_ARM_HAVE_LDREX.
* src/atomic_ops/sysdeps/gcc/generic-arithm.h: Regenerate.
* src/atomic_ops/sysdeps/gcc/generic-arithm.template
(AO_XSIZE_and_XBAR): Do not define if AO_SKIPATOMIC_ANY_and_ANY.
* src/atomic_ops/sysdeps/gcc/generic-arithm.template
(AO_XSIZE_or_XBAR): Do not define if AO_SKIPATOMIC_ANY_or_ANY.
* src/atomic_ops/sysdeps/gcc/generic-arithm.template
(AO_XSIZE_xor_XBAR): Do not define if AO_SKIPATOMIC_ANY_xor_ANY.