Use libm_alias_double for dbl-64 fma.

Use libm_alias_double for dbl-64 fma.

This patch makes dbl-64 fma use libm_alias_double.  The ldbl-opt
version is removed.  The sparc32 version no longer needs to handle
compat symbols, while alpha needs a new wrapper to avoid getting the
ldbl-128 version (where ldbl-opt is earlier in the list of sysdeps
directories, so previously fma came from there).

Tested for x86_64, and tested with build-many-glibcs.py that installed
stripped shared libraries are unchanged by the patch.

	* sysdeps/ieee754/dbl-64/s_fma.c: Include <libm-alias-double.h>.
	(fma): Define using libm_alias_double.
	* sysdeps/ieee754/ldbl-opt/s_fma.c: Remove file.
	* sysdeps/sparc/sparc32/fpu/s_fma.c: Do not include
	<math_ldbl_opt.h>.
	(fmal): Do not define as compat symbol here.
	* sysdeps/alpha/fpu/s_fma.c: New file.