Step 0: mk/ Update Minix platform definition

We are transitionning from a full platform to a NetBSD variant,
per the project policy of having a NetBSD userland. There is then
little meaning in adapting all the NetBSD tests to also be true for
Minix.

This means the following is set as:
 * OPSYS = NetBSD
 * OS_VARIANT = Minix

This also has the consequence of obsoleting a few files in
pkgtools/bootstrap-mk-files.

mk/platform/Minix.mk

@@ -1,47 +0,0 @@
-# $NetBSD: Minix.mk,v 1.6 2016/03/10 16:58:19 jperkin Exp $
-#
-# Variable definitions for the Minix operating system.
-
-ECHO_N?=	${ECHO} -n
-X11_TYPE?=	native
-IMAKE_MAKE?=	${MAKE}	# program which gets invoked by imake
-IMAKEOPTS+=	-DBuildHtmlManPages=NO
-PKGLOCALEDIR?=	share
-PS?=		/usr/bin/ps
-SU?=		/usr/bin/su
-TYPE?=		type			# Shell builtin
-
-CPP_PRECOMP_FLAGS?=	# unset
-DEF_UMASK?=		022
-DEFAULT_SERIAL_DEVICE?=	/dev/null
-EXPORT_SYMBOLS_LDFLAGS?=	# Don't add symbols to the dynamic symbol table
-GROUPADD?=		/usr/sbin/groupadd
-NOLOGIN?=		/bin/false
-PKG_TOOLS_BIN?=		${LOCALBASE}/sbin
-ROOT_CMD?=		${SU} - root -c
-ROOT_GROUP?=	operator
-ROOT_USER?=		root
-SERIAL_DEVICES?=	/dev/null
-USERADD?=		/usr/sbin/useradd
-ULIMIT_CMD_datasize?=	: 
-ULIMIT_CMD_stacksize?=	: 
-
-_OPSYS_SYSTEM_RPATH?=	/usr/lib
-_OPSYS_LIB_DIRS?=	/usr/lib
-_OPSYS_INCLUDE_DIRS?=	/usr/include
-
-_OPSYS_HAS_INET6=	no	# IPv6 is not standard
-_OPSYS_HAS_JAVA=	no	# Java is not standard
-_OPSYS_HAS_MANZ=	no	# no MANZ for gzipping of man pages
-_OPSYS_HAS_OSSAUDIO=	no	# libossaudio is available
-_OPSYS_PERL_REQD=		# no base version of perl required
-_OPSYS_PTHREAD_AUTO=	no	# -lpthread needed for pthreads
-_OPSYS_SHLIB_TYPE=	ELF	# ELF shared libraries on Minix
-_PATCH_CAN_BACKUP=	yes	# native patch(1) can make backups
-_PATCH_BACKUP_ARG?= 	-b -V simple --suffix	# switch to patch(1) for backup suffix
-_USE_RPATH=		yes	# add rpath to LDFLAGS
-
-_STRIPFLAG_CC?=		${_INSTALL_UNSTRIPPED:D:U-s}	# cc(1) option to strip
-_STRIPFLAG_INSTALL?=	${_INSTALL_UNSTRIPPED:D:U-s}	# install(1) option to strip
-
-_OPSYS_CAN_CHECK_SHLIBS=	yes