Don't include math.h/math_private.h in math_ldbl_opt.h.

The sysdeps/ieee754/ldbl-opt version of math_ldbl_opt.h includes
math.h and math_private.h, despite not having any need for those
headers itself; the sysdeps/generic version doesn't.  About 20 files
are relying on math_ldbl_opt.h to include math.h and/or math_private.h
for them, even though none of them necessarily used on a platform that
needs ldbl-opt support.

	* sysdeps/ieee754/ldbl-opt/math_ldbl_opt.h: Don't include
	math.h or math_private.h.

	* sysdeps/alpha/fpu/s_isnan.c
	* sysdeps/ieee754/ldbl-128ibm/s_ceill.c
	* sysdeps/ieee754/ldbl-128ibm/s_floorl.c
	* sysdeps/ieee754/ldbl-128ibm/s_llrintl.c
	* sysdeps/ieee754/ldbl-128ibm/s_llroundl.c
	* sysdeps/ieee754/ldbl-128ibm/s_lrintl.c
	* sysdeps/ieee754/ldbl-128ibm/s_lroundl.c
	* sysdeps/ieee754/ldbl-128ibm/s_rintl.c
	* sysdeps/ieee754/ldbl-128ibm/s_roundl.c
	* sysdeps/ieee754/ldbl-128ibm/s_truncl.c
	* sysdeps/powerpc/powerpc32/power4/fpu/multiarch/e_hypot.c
	* sysdeps/powerpc/powerpc32/power4/fpu/multiarch/e_hypotf.c:
	* sysdeps/powerpc/powerpc64/fpu/multiarch/e_expf.c
	* sysdeps/powerpc/powerpc64/fpu/multiarch/e_hypot.c
	* sysdeps/powerpc/powerpc64/fpu/multiarch/e_hypotf.c:
	Include math_private.h.

	* sysdeps/ieee754/ldbl-64-128/s_finitel.c
	* sysdeps/ieee754/ldbl-64-128/s_fpclassifyl.c
	* sysdeps/ieee754/ldbl-64-128/s_isinfl.c
	* sysdeps/ieee754/ldbl-64-128/s_isnanl.c
	* sysdeps/ieee754/ldbl-64-128/s_signbitl.c
	* sysdeps/powerpc/power7/fpu/s_logb.c:
	Include math.h and math_private.h.