tst-tlsopt-powerpc as a shared lib

tst-tlsopt-powerpc as a shared lib

This makes the __tls_get_addr_opt test run as a shared library, and so
actually test that DTPMOD64/DTPREL64 pairs are processed by ld.so to
support the __tls_get_adfr_opt call stub fast return.  After a
2017-01-24 patch (binutils f0158f4416) ld.bfd no longer emitted
unnecessary dynamic relocations against local thread variables,
instead setting up the __tls_index GOT entries for the call stub fast
return.  This meant tst-tlsopt-powerpc passed but did not check ld.so
relocation support.  After a 2017-07-16 patch (binutils 676ee2b5fa)
ld.bfd no longer set up the __tls_index GOT entries for the call stub
fast return, and tst-tlsopt-powerpc failed.

Compiling mod-tlsopt-powerpc.c with -DSHARED exposed a bug in
powerpc64/tls-macros.h, which defines a __TLS_GET_ADDR macro that
clashes with one defined in dl-tls.h.  The tls-macros.h version is
only used in that file, so delete it and expand.

	* sysdeps/powerpc/mod-tlsopt-powerpc.c: Extract from
	tst-tlsopt-powerpc.c with function name change and no test harness.
	* sysdeps/powerpc/tst-tlsopt-powerpc.c: Remove body of test.
	Call tls_get_addr_opt_test.
	* sysdeps/powerpc/Makefile (LDFLAGS-tst-tlsopt-powerpc): Don't define.
	(modules-names): Add mod-tlsopt-powerpc.
	(mod-tlsopt-powerpc.so-no-z-defs): Define.
	(tst-tlsopt-powerpc): Depend on .so.
	* sysdeps/powerpc/powerpc64/tls-macros.h (__TLS_GET_ADDR): Don't
	define.  Expand use in TLS_GD and TLS_LD.