x11/wvkbd: add hook for out-of-tree patches

x11/wvkbd/Makefile

@@ -17,6 +17,7 @@ LIB_DEPENDS=	libepoll-shim.so:devel/libepoll-shim \
 
 USES=		gmake gnome pkgconfig
 USE_GNOME=	cairo pango
+EXTRA_PATCHES=	${${PORTNAME:tu}_PATCHES}
 MAKE_ARGS=	VERSION="${DISTVERSIONFULL}"
 PLIST_FILES=	bin/${PORTNAME}-mobintl \
 		share/man/man1/${PORTNAME}.1.gz
@@ -26,6 +27,10 @@ pre-everything::
 	@${ECHO_MSG} "To build ${PORTNAME} with your own config.h set ${PORTNAME:tu}_CONF variable"
 	@${ECHO_MSG} "either in ${.CURDIR:T}/Makefile.local, make.conf(5), environ(7) or command line e.g.,"
 	@${ECHO_MSG} "\$$ make install clean ${PORTNAME:tu}_CONF=/path/to/${PORTNAME}/config.h"
+	@${ECHO_MSG}
+	@${ECHO_MSG} "To apply your own patches set ${PORTNAME:tu}_PATCHES (like ${PORTNAME:tu}_CONF)"
+	@${ECHO_MSG} "to a list of files separated by space with optional -pX suffix e.g.,"
+	@${ECHO_MSG} "\$$ make install clean ${PORTNAME:tu}_PATCHES='/path/to/foo.patch:-p1'"
 
 post-extract:
 # .if exists(...) before bsd.port.mk ignores *_CONF in make.conf(5) and Makefile.local