MFC -fno-common fixes: r359389, r359394, r359397-r359399, r359403-r359404,
r359406, r359413-r359416, r359425, r359427, r359432-r359433, r359443,
r359675-r359677

Note: this is not necessarily a complete fix to get these programs to build
with -fno-common applied.

r359389:
config(8): fixes for -fno-common

Move this handful of definitions into main.c, properly declare these as
extern in config.h. This fixes the config(8) build with -fno-common.

Unexplained in my previous commit to gas, -fno-common will become the
default in GCC10 and LLVM11, so it's worth addressing these in advance.

r359394:
MFV r359393: tcsh: import 6974bc35a5cd

This removes an extra variable definition that causes the -fno-common build
to fail, which will be a new default in GCC10/LLVM11.

r359397:
zfs: fix -fno-common issues

A similar (or identical?) fix has already landed in OpenZFS.

-fno-common will become the default in GCC10/LLVM11.

r359398:
sh: remove duplicate el definition

el is declared extern in myhistedit.h and defined in histedit.c. Remove the
duplicate definition in input.c to appease the -fno-common build.

-fno-common will become the default in GCC10/LLVM11.

r359399:
telnet: remove some duplicate definitions, mark terminaltype extern

Most of these were already properly declared and defined elsewhere, this is
effectively just a minor cleanup that fixes the -fno-common build.

-fno-common will become the default in GCC10/LLVM11.

r359403:
Revert 359399: telnet -fno-common bits

There was a large misfire from my local diff that I need to investigate, and
this version committed did not build.

r359404:
Re-apply r359399: telnet -fno-common fix

line and auth_level's redefinitions are just extraneous

telnetd will #define extern and then include ext.h to allocate storage for
all of these extern'd vars; however, two of them are actually defined in
libtelnet instead. Instead of doing an #ifdef extern dance around those
function pointers, just add an EXTERN macro to make it easier to
differentiate by sight which ones will get allocated in globals.c and which
ones are defined elsewhere.

r359406:
telnet: kill off remaining duplicate definition

r359413:
ipfilter: remove duplicate definition of 'thishost'

thishost is already defined in lib/initparse.c; no need for this one. This
fixes the ipfilter build with -fno-common.

-fno-common will become the default in GCC10/LLVM11.

r359414:
iscontrol: move definition of vflag/iscsidev to iscontrol.c

Mark the declaration extern as these are used elsewhere; this fixes the
build with -fno-common.

r359415:
userboot: mark host_fsops as extern

This is already defined elsewhere; mark this declaration extern to the fix
the -fno-common build.

r359416:
systat: remove redundant definition of kd

kd is already properly declared in extern.h and defined in main.c, rendering
this definition useless. This fixes the -fno-common build.

r359425:
locate: fix -fno-common build

Just a single variable declaration to extern and define elsewhere here,
myctype.

-fno-common will become a default in GCC10/LLVM11.

r359427:
fsck_ffs/fsdb: fix -fno-common build

This one is also a small list:

- 3x duplicate definition (ufs2_zino, returntosingle, nflag)
- 5x 'needs extern', 3/5 of which are referenced in fsdb

-fno-common will become the default in GCC10/LLVM11.

r359432:
gdb: compile with -fcommon explicitly

As described in the comment, gdb relies on some of the linker magic that
happens with -fcommon. I suspect the life expectancy of gdb-in-base is low
enough that this isn't worth spending much time addressing, especially given
the vintage. Hit it with the -fcommon hammer so that it continues to just
work.

r359433:
bmake: fix -fno-common build

debug was declared extern, but debug_file was not; correct this and define
debug_file in main.c (as debug is) to fix the -fno-common build.

-fno-common will become the default with GCC10/LLVM11.

r359443:
MFV r359442: bmake: import -fno-common fix build back from upstream

sjg@ committed the local patch previously committed upstream; pull it in to
vendor/ to ease any potential stress of future imports.

r359675:
kqueue tests: fix -fno-common build

vnode_fd and kqfd are both shared among multiple CU; define them exactly
once.

In the case of vnode_fd, it was simply the declaration that needed
correction.

-fno-common will become the default in GCC10/LLVM11.

r359676:
ntpd: fix build with -fno-common

Only a small nit here: psl should be declared extern and defined exactly
once.

-fno-common will become the default in GCC10/LLVM11.

r359677:
yp*: fix -fno-common build

This is mostly two problems spread out far and wide:
- ypldap_process should be declared properly
- debug is defined differently in many programs

For the latter, just extern it and define it everywhere that actually needs
it. This mostly works out nicely for ^/libexec/ypxfr, which can remove the
assignment at the beginning of main in favor of defining it properly.

-fno-common will become the default in GCC10/LLVM11.

MFC of 347064, 347066, and 347130

Avoid leaking kernel stack when creating directory names.

MFC of 344552 and 344732

Have fsck_ffs adjust size for files with hole at end

Tighten last lbn calculation

Sponsored by: Netflix

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 r317283:
fsck_ffs: Unsign some variables and make use of reallocarray(3).

Instead of casting listmax and numdirs to unsigned values just define
them as unsigned and avoid the casts. Use reallocarray(3).

While here, fs_ncg is already unsigned so the cast is unnecessary.

Reviewed by: mckusick

MFC 304438:

Fsck_ufs was using an int rather than a ufs2_daddr_t to store the
alternate superblock location when given in the -b option.

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

Cleanup unnecessary semicolons from utilities we all love.

Fix a ton of speelling errors

arc lint is helpful

Reviewed By: allanjude, wblock, #manpages, chris@bsdjunk.com
Differential Revision: https://reviews.freebsd.org/D3337

Add globs.c, missed in r260068,260069

Submitted by: peter
Obtained from: Netflix
MFC after: 3 Days