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

MFC r328052: kldxref: handle modules with md_cval at end of allocated secs

Attempting to retrieve an md_cval string from a kernel module with
kldxref would throw a offset error for modules created using lld, since
this value would be placed at the end of all allocated sections.

Add an ef_read_seg_string method to the ef interface, to allow reading
strings of varying size without attempting to read beyond the segment's
bounds.

PR: 224875
Submitted by: Mitchell Horne <mhorne063@gmail.com>
Sponsored by: The FreeBSD Foundation

MFC r327503: kldxref: correct function names in warning messages

Sponsored by: The FreeBSD Foundation

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

Use calloc().

MFC after: 2 weeks

Remove unneeded reference to link.h (sys/link_elf.h).

MFC after: 2 weeks

fix a couple of innocuous compiler warnings

MFC after: 3 days

Use posix_memalign() rather than assuming that malloc() provides adequate
alignment.

Approved by: markm (mentor)

Make our ELF64 type definitions match standards. In particular this
means:
o Remove Elf64_Quarter,
o Redefine Elf64_Half to be 16-bit,
o Redefine Elf64_Word to be 32-bit,
o Add Elf64_Xword and Elf64_Sxword for 64-bit entities,
o Use Elf_Size in MI code to abstract the difference between
Elf32_Word and Elf64_Word.
o Add Elf_Ssize as the signed counterpart of Elf_Size.

MFC after: 2 weeks

Explicitly pass in the relocation base and data offset into ef_reloc()
rather than relying on a trick that happens to work for the current
relocation schemes. Also add some comments and improve variable
naming.

Use a temporary void * variable to work around a strict aliasing
warning that gcc generates at -O2 and higher.

Add support for reading ELF relocatable object file format modules.