Add sanity checks for chroot/jail building and stop asking kernel for OSVERSION.

[bdrewery]

Summary

If either of OSVERSION or UNAME_r is improperly set when building in a
jail/chroot, a number of unexpected errors can occur.

1. autotools fixup may not run when needed. This could be avoided by always running it [PR 177980, 177403]
2. Not having UNAME_r set will cause many unknown errors. Many ports use OSREL (derived from UNAME_r) to determine the name of files. This is usually also due to the port build itself using uname -r to derive filenames or 'built for' messages. [PR 192449, 191943]

Without having these sanity checks it is very easy for users to get into
situations where "everything worked" until they touch a certain port that
reads uname or OSVERSION. It has always been necessary to define all of the
UNAME_ vars and OSVERSION (or have a proper sys/param.h present), but many
users do not know this.

Remove the fallback on the kernel for kern.osreldate as it easily gets the
answer wrong.

I have added sanity checks to ensure OSVERSION==OSREL==UNAME_r as these are the
most critical vars to have set properly.

Test Plan

Built cross-release in poudriere and on host.

uname -r; make OSVERSION=1000036 OSREL="11" clean

11.0-CURRENT
make: "/root/svn/ports/Mk/bsd.port.mk" line 1206: UNAME_r (11.0-CURRENT) and OSVERSION (1000036) do not agree on major version number.

uname -r;make OSVERSION=1000036 clean

11.0-CURRENT
make: "/root/svn/ports/Mk/bsd.port.mk" line 1206: UNAME_r (11.0-CURRENT) and OSVERSION (1000036) do not agree on major version number.

make OSVERSION=1000036 OSREL="11" UNAME_r="10.0-STABLE" clean

make: "/root/svn/ports/Mk/bsd.port.mk" line 1208: OSREL (11) and OSVERSION (1000036) do not agree on major version number.

make OSVERSION=1000036 UNAME_r="10.0-STABLE" clean

> Cleaning for beadm-1.1_1

make OSVERSION=1000036 OSREL="10" UNAME_r="10.0-STABLE" clean

> Cleaning for beadm-1.1_1

1. mv /usr/include/sys/param.h{,.old}
2. make -V SRC_BASE -V OSVERSION

/usr/src
1100036

make -V SRC_BASE -V OSVERSION SRC_BASE=/nonexistent

make: "/root/svn/ports/Mk/bsd.port.mk" line 1201: Unable to determine os version. Either define OSVERSION or install /usr/include/sys/param.h

make -V SRC_BASE -V OSVERSION SRC_BASE=/nonexistent OSVERSION=1000036

make: "/root/svn/ports/Mk/bsd.port.mk" line 1206: UNAME_r (11.0-CURRENT) and OSVERSION (1000036) do not agree on major version number.

make -V SRC_BASE -V OSVERSION SRC_BASE=/nonexistent OSVERSION=1000036 UNAME_r="10.0-STABLE"

/nonexistent
1000036

[antoine]

Mk/bsd.port.mk

1206

${OSVERSION:C/([0-9]*)[0-9]{5}/\1/} is simpler and does the same?

[bdrewery]

Fix OSREL assignment.

[gjb]

At quick (untested) review, this looks good to me.

[bapt]

At least handling case like 5.2.1 should be done

Mk/bsd.port.mk

1201

This should be IGNORE to be consistent (I know the IGNORE variable sucks)
Or .error should be a propagated usage

1208

That will fail in case of the 11.1.1 release (which already happened in the past aka 5.2.1)

[bdrewery]

Mk/bsd.port.mk

1201

IGNORE does not work here. What is the problem with .error?

1208

I don't think so. The intent is to only grab the first 2 numbers since we have ABI stability on those.
sys/sys/param.h: scheme is: <major><two digit minor>Rxx
Major may be 1 or 2 long, the rest are fixed-width.

[bapt]

Mk/bsd.port.mk

1201

.error is probably ok

[bdrewery]

Committed in P369644