Add a generic scalb implementation

This is a preparatory patch to enable building a _Float128
variant to ease reuse when building a _Float128 variant to
alias this long double only symbol.

Notably, stubs are added where missing to the native _Float128
sysdep dir to prevent building these newly templated variants
created inside the build directories.

Also noteworthy are the changes around LIBM_SVID_COMPAT.  These
changes are not intuitive.  The templated version is only
enabled when !LIBM_SVID_COMPAT, and the compat version is
predicated entirely on LIBM_SVID_COMPAT.  Thus, exactly one is
stubbed out entirely when building.  The nldbl scalb compat
files are updated to account for this.

Likewise, fixup the reuse of m68k's e_scalb{f,l}.c to include
it's override of e_scalb.c.  Otherwise, the search path finds
the templated copy in the build directory.  This could be
futher simplified by providing an overridden template, but I
lack the hardware to verify.

1 files changed, 0 insertions, 54 deletions

diff --git a/math/e_scalbl.c b/math/e_scalbl.c
deleted file mode 100644
index 6595ec6c27..0000000000
--- a/math/e_scalbl.c
+++ /dev/null
@@ -1,54 +0,0 @@
-/* Copyright (C) 2011-2020 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-   Contributed by Ulrich Drepper <drepper@gmail.com>, 2011.
-
-   The GNU C Library is free software; you can redistribute it and/or
-   modify it under the terms of the GNU Lesser General Public
-   License as published by the Free Software Foundation; either
-   version 2.1 of the License, or (at your option) any later version.
-
-   The GNU C Library is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-   Lesser General Public License for more details.
-
-   You should have received a copy of the GNU Lesser General Public
-   License along with the GNU C Library; if not, see
-   <https://www.gnu.org/licenses/>.  */
-
-#include <math.h>
-#include <math_private.h>
-#include <libm-alias-finite.h>
-
-static long double
-__attribute__ ((noinline))
-invalid_fn (long double x, long double fn)
-{
-  if (rintl (fn) != fn)
-    return (fn - fn) / (fn - fn);
-  else if (fn > 65000.0L)
-    return __scalbnl (x, 65000);
-  else
-    return __scalbnl (x,-65000);
-}
-
-
-long double
-__ieee754_scalbl (long double x, long double fn)
-{
-  if (__glibc_unlikely (isnan (x)))
-    return x * fn;
-  if (__glibc_unlikely (!isfinite (fn)))
-    {
-      if (isnan (fn) || fn > 0.0L)
-	return x * fn;
-      if (x == 0.0L)
-	return x;
-      return x / -fn;
-    }
-  if (__glibc_unlikely (fabsl (fn) >= 0x1p31L || (long double) (int) fn != fn))
-    return invalid_fn (x, fn);
-
-  return __scalbnl (x, (int) fn);
-}
-libm_alias_finite (__ieee754_scalbl, __scalbl)