Revert r330897:

This was intended to be a non-functional change. It wasn't. The commit
message was thus wrong. In addition it broke arm, and merged crypto
related code.

Revert with prejudice.

This revert skips files touched in r316370 since that commit was since
MFCed. This revert also skips files that require $FreeBSD$ property
changes.

Thank you to those who helped me get out of this mess including but not
limited to gonzo, kevans, rgrimes.

Requested by: gjb (re)

Partial merge of the SPDX changes

These changes are incomplete but are making it difficult
to determine what other changes can/should be merged.

No objections from: pfg

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Unbreak the build for arm and powerpc.

Pointy hat to yours truly.

Make several changes to the way printf handles hex floating point (%a):

1. Previously, printing the number 1.0 could produce 0x1p+0, 0x2p-1,
0x4p-2, or 0x8p-3, depending on what happened to be convenient. This
meant that printing a value as a double and printing the same value
as a long double could produce different (but equivalent) results.
The change is to always make the leading digit a 1, unless the
number is 0. This solves the aforementioned problem and has
several other advantages.

2. Use the FPU to do rounding. This is far simpler and more portable
than manipulating the bits, and it fixes an obsure round-to-even
bug. It also raises the exceptions now required by IEEE 754R.
The drawbacks are that it is usually slightly slower, and it makes
printf less effective as a debugging tool when the FPU is hosed
(e.g., due to a buggy softfloat implementation).

3. On i386, twiddle the rounding precision so that (2) works properly
for long doubles.

4. Make several simplifications that are now possible due to (2).

5. Split __hldtoa() into a separate file.

Thanks to remko for access to a sparc64 box for testing.

Fix a rounding error.

Reported by: Bruno Haible

Fix rounding of 0xf for hex fp formats.

PR: 90333

Cut out the gordian handling of subnormals by bit fiddling, and
instead use the FPU to convert subnormals to normals. (NB: Further
simplification is possible, such as using the FPU for the rounding
step.)

This fixes a bug reported by stefanf where long double subnormals in
the Intel 80-bit format would be output with one fewer digit than
necessary when the default precision was used.

Updated manh shift constant type to 'ULL' for PPC to fix
shift-too-large compile error

reviewed by: das

Implement __hdtoa() and __hldtoa() and enable printf() support for %a
and %A, which print floating-point numbers in hexadecimal.