Index: Makefile
===================================================================
--- Makefile	(revision 566284)
+++ Makefile	(working copy)
@@ -117,7 +117,7 @@
 USE_PERL5=	build
 USE_XORG=	ice sm x11 xaw xcb xext xinerama xrandr xrender
 
-OPTIONS_DEFINE=	COINMP CUPS DOCS GNOME GTK3 JAVA KF5 MMEDIA PGSQL QT5 SDK TEST WEBDAV
+OPTIONS_DEFINE=	COINMP CUPS DOCS GNOME GTK3 JAVA KF5 LTO MMEDIA PGSQL QT5 SDK TEST WEBDAV
 OPTIONS_DEFAULT=	CUPS MMEDIA QT5
 
 .if !defined(DEFAULT_VERSIONS) || ! ${DEFAULT_VERSIONS:Mssl=*}
@@ -200,6 +200,8 @@
 KF5_USES=	kde:5
 KF5_IMPLIES=	QT5
 
+LTO_CONFIGURE_ENABLE=	lto
+
 MMEDIA_CONFIGURE_ENABLE=	gstreamer-1-0
 MMEDIA_USE=	GSTREAMER1=yes
 
@@ -287,6 +289,14 @@
 CONFIGURE_ARGS+=	--disable-skia
 .endif
 
+.if ${PORT_OPTIONS:MLTO} && ${CHOSEN_COMPILER_TYPE} == clang
+CPP=	${LOCALBASE}/bin/clang-cpp${LLVM_DEFAULT}
+CC=	${LOCALBASE}/bin/clang${LLVM_DEFAULT}
+CXX=	${LOCALBASE}/bin/clang++${LLVM_DEFAULT}
+BUILD_DEPENDS+=	${LOCALBASE}/bin/clang${LLVM_DEFAULT}:devel/llvm${LLVM_DEFAULT}
+LLD_UNSAFE=	yes
+.endif
+
 .if ${CHOSEN_COMPILER_TYPE} == clang
 CXXFLAGS_WARN=	-Woverloaded-virtual -Wno-unused-parameter -Wno-unused-local-typedefs
 .else