which: Use size_t instead of ssize_t for pathlen

The "pathlen" variable is the return value of strlen(3) and is then
passed as an argument to malloc(3) and memcpy(3). The size_t type
matches the prototype for these functions. The size_t type is unsigned
so it can fit larger $PATH values than ssize_t. However, in practice
ssize_t should be larger enough so this change is just for clarity.

Signed-off-by: Collin Funk <collin.funk1@gmail.com>

MFC after: 1 week
Pull Request: https://github.com/freebsd/freebsd-src/pull/1113

Remove $FreeBSD$: two-line .c pattern

Remove /^#include\s+<sys/cdefs.h>.*$\n\s+__FBSDID\("\$FreeBSD\$"\);\n/

various: general adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

No functional change intended.

which(1): sort #includes

No functional change [intended].

MFC after: 7 weeks
Sponsored by: Dell EMC Isilon

Clean up trailing whitespace

No functional changes

MFC after: 1 week
Sponsored by: Dell EMC Isilon

Mark global functions and/or variables in which(1) static where possible.

This allows compilers and static analyzers to more thorough analysis.

A new jail(8) with a configuration file, to replace the work currently done
by /etc/rc.d/jail.

Create the altix project branch. The altix project will add support
for the SGI Altix 350 to FreeBSD/ia64. The hardware used for porting
is a two-module system, consisting of a base compute module and a
CPU expansion module. SGI's NUMAFlex architecture can be an excellent
platform to test CPU affinity and NUMA-aware features in FreeBSD.

- Import the HEAD csup code which is the basis for the cvsmode work.

Require at least one argument.

Handle relative and absolute pathnames (anything with a `/' in it) in the same
way as execve(2), and the old perl which(1).

PR: 35718

Treat empty PATH elements as "." for tradition and consistency with the
old Perl which(1) script.

PR: 35719

Off by one error in checking max file name length.

Use FBSDID(), WARNS=2 fix.

Mkaefile does not use WARNS=2 beacuse this will be made default.

Use a C version of which(1).

Submitted by: Dan Papasian <bugg@bugg.strangled.net>
Reviewed by: jhb