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

Use stdint.h instead of inttypes.h as the latter pollutes namespace more

MFC after: 3 days
X-MFC with: r292004
Submitted by: bde
Sponsored by: EMC / Isilon Storage Division

Fix compilation when -DDEBUG is defined by adding inttypes.h #include
for intmax_t

MFC after: 3 days
Differential Revision: https://reviews.freebsd.org/D4434
Reported by: cppcheck
Reviewed by: jhb
Sponsored by: EMC / Isilon Storage Division

Reassign copyright statements on several files from Advanced
Computing Technologies LLC to Hudson River Trading LLC.

Approved by: Hudson River Trading LLC (who owns ACT LLC)
MFC after: 1 week

Add an implementation of open_memstream() and open_wmemstream(). These
routines provide write-only stdio FILE objects that store their data in a
dynamically allocated buffer. They are a string builder interface somewhat
akin to a completely dynamic sbuf.

Reviewed by: bde, jilles (earlier versions)
MFC after: 1 month