Replace "${OPSYS:tl}" with "freebsd" on 4 ports

The following 4 ports will not build correctly if certain variables
are not defined as "freebsd".  Defining them as "${OPSYS:tl}" caused
breakage on DragonFly for various reasons.  Harding the variables are
a no-op for FreeBSD but fixes the ports on DragonFly.

* games/ioquake3
* graphics/opendx
* science/cdf
* security/john

approved by:	portmgr (bapt)

games/ioquake3/Makefile

@@ -62,7 +62,7 @@ ALL_TARGET=	release
 
 LIBDIR=		lib/${PORTNAME}${PKGNAMESUFFIX}
 DOCSDIR=	share/doc/${PORTNAME}${PKGNAMESUFFIX}
-BUILDDIR=	${WRKSRC}/build/${ALL_TARGET}-${OPSYS:tl}-${IOQ3ARCH}
+BUILDDIR=	${WRKSRC}/build/${ALL_TARGET}-freebsd-${IOQ3ARCH}
 BINSUFFIX?=
 HOMEPATH?=	/.${PORTNAME}
 Q3CLIENT?=	ioquake3

graphics/opendx/Makefile

@@ -22,11 +22,11 @@ USE_GL=		yes
 USE_AUTOTOOLS=	libtool
 USE_LDCONFIG=	yes
 CFLAGS+=	${PTHREAD_CFLAGS}
-CONFIGURE_ENV=	ARCH="${OPSYS:tl}"
+CONFIGURE_ENV=	ARCH=freebsd
 CPPFLAGS+=	${CXXFLAGS} -I${LOCALBASE}/include
 LDFLAGS+=	-L${LOCALBASE}/lib
 NO_MTREE=	yes
-PLIST_SUB=	ARCH=${OPSYS:tl}
+PLIST_SUB=	ARCH=freebsd
 PKGMESSAGE=	${WRKDIR}/pkg-message
 
 .if defined(WITH_HDF) && !defined(WITHOUT_NETCDF)

science/cdf/Makefile

@@ -14,7 +14,7 @@ DIST_SUBDIR=	${PORTNAME}-${PORTVERSION}
 MAINTAINER=	stephen@FreeBSD.org
 COMMENT=	Device independent view of the CDF data model
 
-MAKE_FLAGS=	INSTALLDIR=${STAGEDIR}${PREFIX} OS=${OPSYS:tl} ENV=gnu      \
+MAKE_FLAGS=	INSTALLDIR=${STAGEDIR}${PREFIX} OS=freebsd ENV=gnu      \
 		FORTRAN=yes FC_freebsd=${F77}
 USE_LDCONFIG=	yes
 MAKE_JOBS_UNSAFE=	yes

security/john/Makefile

@@ -27,7 +27,7 @@ BUILD_WRKSRC=	${WRKDIR}/${DISTNAME}/src
 #
 PORTSCOUT=	limit:.*-jumbo
 
-OSNAME=		${OPSYS:tl}
+OSNAME=		freebsd
 CFLAGS+=	-DJOHN_SYSTEMWIDE=1 \
 		-DJOHN_SYSTEMWIDE_HOME=\\"${DATADIR}\\" \
 		-DCFG_FULL_NAME=\\"${PREFIX}/etc/${PORTNAME}.conf\\"