Index: head/CHANGES
===================================================================
--- head/CHANGES
+++ head/CHANGES
@@ -10,6 +10,20 @@
 
 All ports committers are allowed to commit to this file.
 
+20171231:
+AUTHOR: kde@FreeBSD.org
+
+  USES=cmake now supports two additional list variables: 
+    * CMAKE_ON  : List of variables to turn on
+    * CMAKE_OFF : List of variables to turn off
+  This can be used as a shortcut to append these to CMAKE_ARGS.
+
+  For example ports that previously set 
+    CMAKE_ARGS=		-DVAR1:BOOL=TRUE -DVAR2:BOOL=TRUE -DVAR3:BOOL=FALSE
+  can now set this as
+    CMAKE_ON=		VAR1 VAR2
+    CMAKE_OFF=		VAR3
+
 20171130:
 AUTHOR: mat@FreeBSD.org
 
Index: head/Mk/Uses/cmake.mk
===================================================================
--- head/Mk/Uses/cmake.mk
+++ head/Mk/Uses/cmake.mk
@@ -25,6 +25,8 @@
 #			Default: not set, unless BATCH or PACKAGE_BUILDING is defined
 #
 # Variables for ports:
+# CMAKE_ON		Appends -D<var>:bool=ON  to the CMAKE_ARGS,
+# CMAKE_OFF		Appends -D<var>:bool=OFF to the CMAKE_ARGS.
 # CMAKE_ARGS		- Arguments passed to cmake
 #			Default: see below
 # CMAKE_BUILD_TYPE	- Type of build (cmake predefined build types).
@@ -88,6 +90,13 @@
 			-DTHREADS_HAVE_PTHREAD_ARG:BOOL=YES \
 			-DCMAKE_INSTALL_RPATH_USE_LINK_PATH=YES \
 			-DCMAKE_VERBOSE_MAKEFILE:BOOL=ON
+
+# Handle the option-like CMAKE_ON and CMAKE_OFF lists.
+.for _bool_kind in ON OFF
+.  if defined(CMAKE_${_bool_kind})
+CMAKE_ARGS+=		${CMAKE_${_bool_kind}:C/.*/-D&:BOOL=${_bool_kind}/}
+.  endif
+.endfor
 
 CMAKE_INSTALL_PREFIX?=	${PREFIX}