Move fenv.h soft-float inlines from fenv_private.h to include/fenv.h.

Move fenv.h soft-float inlines from fenv_private.h to include/fenv.h.

<fenv_private.h> has inline versions of various <fenv.h> functions,
and their __fe* variants, for systems (generally soft-float) without
support for floating-point exceptions, rounding modes or both.

Having these inlines in a separate header introduces a risk of a
source file including <fenv.h> and compiling OK on x86_64, but failing
to compile (because the feraiseexcept inline is actually a macro that
discards its argument, to avoid the need for #ifdef FE_INVALID
conditionals), or not being properly optimized, on systems without the
exceptions and rounding modes support (when these inlines were in
math_private.h, we had a few cases where this broke the build because
there was no obvious reason for a file to need math_private.h and it
didn't need that header on x86_64).  By moving those inlines to
include/fenv.h, this risk can be avoided, and fenv_private.h becomes
more clearly defined as specifically the header for the internal
libc_fe* and SET_RESTORE_ROUND* interfaces.

This patch makes that move, removing fenv_private.h includes that are
no longer needed (or replacing them by fenv.h includes in a few cases
that didn't already have such an include).

Tested for x86_64 and x86, and tested with build-many-glibcs.py that
installed stripped shared libraries are unchanged by the patch.

	* sysdeps/generic/fenv_private.h [FE_ALL_EXCEPT == 0]: Move this
	code ....
	[!FE_HAVE_ROUNDING_MODES]: And this code ....
	* include/fenv.h [!_ISOMAC]: ... to here.
	* math/fraiseexcpt.c (__feraiseexcept): Undefine as macro.
	(feraiseexcept): Likewise.
	* math/fromfp.h: Do not include <fenv_private.h>.
	* math/s_cexp_template.c: Likewise.
	* math/s_csin_template.c: Likewise.
	* math/s_csinh_template.c: Likewise.
	* math/s_ctan_template.c: Likewise.
	* math/s_ctanh_template.c: Likewise.
	* math/s_iseqsig_template.c: Likewise.
	* math/w_acos_compat.c: Likewise.
	* math/w_acosf_compat.c: Likewise.
	* math/w_acosl_compat.c: Likewise.
	* math/w_asin_compat.c: Likewise.
	* math/w_asinf_compat.c: Likewise.
	* math/w_asinl_compat.c: Likewise.
	* math/w_j0_compat.c: Likewise.
	* math/w_j0f_compat.c: Likewise.
	* math/w_j0l_compat.c: Likewise.
	* math/w_j1_compat.c: Likewise.
	* math/w_j1f_compat.c: Likewise.
	* math/w_j1l_compat.c: Likewise.
	* math/w_jn_compat.c: Likewise.
	* math/w_jnf_compat.c: Likewise.
	* math/w_log10_compat.c: Likewise.
	* math/w_log10f_compat.c: Likewise.
	* math/w_log10l_compat.c: Likewise.
	* math/w_log2_compat.c: Likewise.
	* math/w_log2f_compat.c: Likewise.
	* math/w_log2l_compat.c: Likewise.
	* math/w_log_compat.c: Likewise.
	* math/w_logf_compat.c: Likewise.
	* math/w_logl_compat.c: Likewise.
	* sysdeps/ieee754/dbl-64/s_llrint.c: Likewise.
	* sysdeps/ieee754/dbl-64/s_llround.c: Likewise.
	* sysdeps/ieee754/dbl-64/s_lrint.c: Likewise.
	* sysdeps/ieee754/dbl-64/s_lround.c: Likewise.
	* sysdeps/ieee754/dbl-64/wordsize-64/s_lround.c: Likewise.
	* sysdeps/ieee754/flt-32/s_llrintf.c: Likewise.
	* sysdeps/ieee754/flt-32/s_llroundf.c: Likewise.
	* sysdeps/ieee754/flt-32/s_lrintf.c: Likewise.
	* sysdeps/ieee754/flt-32/s_lroundf.c: Likewise.
	* sysdeps/ieee754/k_standardl.c: Likewise.
	* sysdeps/ieee754/ldbl-128/e_expl.c: Likewise.
	* sysdeps/ieee754/ldbl-128/s_fmal.c: Likewise.
	* sysdeps/ieee754/ldbl-128/s_llrintl.c: Likewise.
	* sysdeps/ieee754/ldbl-128/s_llroundl.c: Likewise.
	* sysdeps/ieee754/ldbl-128/s_lrintl.c: Likewise.
	* sysdeps/ieee754/ldbl-128/s_lroundl.c: Likewise.
	* sysdeps/ieee754/ldbl-128/s_nearbyintl.c: Likewise.
	* sysdeps/ieee754/ldbl-128ibm/s_llrintl.c: Likewise.
	* sysdeps/ieee754/ldbl-128ibm/s_llroundl.c: Likewise.
	* sysdeps/ieee754/ldbl-128ibm/s_lrintl.c: Likewise.
	* sysdeps/ieee754/ldbl-128ibm/s_lroundl.c: Likewise.
	* sysdeps/ieee754/ldbl-96/s_fma.c: Likewise.
	* sysdeps/ieee754/ldbl-96/s_fmal.c: Likewise.
	* sysdeps/ieee754/ldbl-96/s_llrintl.c: Likewise.
	* sysdeps/ieee754/ldbl-96/s_llroundl.c: Likewise.
	* sysdeps/ieee754/ldbl-96/s_lrintl.c: Likewise.
	* sysdeps/ieee754/ldbl-96/s_lroundl.c: Likewise.
	* math/w_ilogb_template.c: Include <fenv.h> instead of
	<fenv_private.h>.
	* math/w_llogb_template.c: Likewise.
	* sysdeps/powerpc/fpu/e_sqrt.c: Likewise.
	* sysdeps/powerpc/fpu/e_sqrtf.c: Likewise.