Makefile.inc1: Handle pkg development versions

Development versions of pkg have a version like "2.3.0-d8bbde1c3-dirty",
which is not handled by PKG_BIN_VERSION, so PKG_EXT ends up being "tar"
and this breaks update-packages.

Fix the PKG_BIN_VERSION logic, and while here, remove backwards compat
for pkg versions prior to 2.0, which no one should be using to build
main or stable/15.  This means nothing is left to use PKG_BIN_VERSION,
but continue to set it, since we might need it again in the future.

MFC after:	1 day
Reviewed by:	manu, kevans
Differential Revision:	https://reviews.freebsd.org/D52666

Makefile.inc1

@@ -2004,12 +2004,8 @@ _pkgbootstrap: .PHONY
 .endif
 
 PKG_BIN_VERSION!=${PKG_CMD} --version </dev/null 2>/dev/null |\
-    awk -F. '/^[0-9.]+$$/ {print $$1 * 10000 + $$2 * 100 + $$3}'
-.if ${PKG_BIN_VERSION} < 11700
-PKG_EXT=	${PKG_FORMAT}
-.else
+    awk -F. '/^[0-9.]+(-.*)?$$/ {print $$1 * 10000 + $$2 * 100 + $$3}'
 PKG_EXT=	pkg
-.endif
 
 .if !defined(PKG_VERSION_FROM) && make(real-update-packages) && \
     exists(${PKG_ABI_FILE}) && exists(${REPODIR}/${PKG_ABI}/latest)
@@ -2371,9 +2367,6 @@ sign-packages:	.PHONY
 
 real-sign-packages:	_pkgbootstrap .PHONY
 	printf "version = 2;\n" > ${WSTAGEDIR}/meta
-.if ${PKG_BIN_VERSION} < 11700
-	printf "packing_format = \"${PKG_FORMAT}\";\n" >> ${WSTAGEDIR}/meta
-.endif
 	@${PKG_CMD} -o ABI=${PKG_ABI} -o OSVERSION="${SRCRELDATE}" \
 		-o WORKERS_COUNT=${PKG_WORKERS_COUNT} repo \
 		-m ${WSTAGEDIR}/meta \