fix tools build

PR/57891: Ricardo Branco: add symbolic flags printing (from FreeBSD)

adapt to ${CC_WNO_IMPLICIT_FALLTHROUGH}

Use ${CC_WNO_IMPLICIT_FALLTHROUGH} instead of
the older style more complex expressions.

Divide stat.1 into stat.1 (now only includes stat(1)) and readlink.1

Apologies to cvs commit purists, but making this division required
line by line reading of the man pages, and I simply could not resist
also correcting some errors, addressing some omissions, improving some
wording ... all at the same time.

convert HAVE_GCC == 7 to HAVE_GCC >= 7.

rework the previous to only apply if !HOSTPROG

apply -Wno-error=implicit-fallthrough on files that have fallthru
comments but are missed by the current checker.

branches: 1.8.42;
document non-literal format strings

More properly host-tool-ify stat

pass in -DHOSTPROG if a HOSTPROG

Fix a tyop - we want the readlink binary and manual pages when HOSTPROG
is not defined.

first attempt at making this a HOSTPROG

NetBSD id police

A new command line option, -q, suppresses *stat(2) failure messages.
Output is now done via stdio, instead of with my stupid homegrown
buffering (I don't even know why I did it that way in the first
place). Also, from Johan Karlsson <johan@freebsd.org>, eliminate a
spurious newline if no output was generated, and link stat(1) to
readlink(1) for similarity to OpenBSD.

Add a stat(1) program to /usr/bin. It provides a simple formatting
interface, with reasonable defaults, to the information provided by
stat(2) so that scripts can use the data therein much more easily.