Add default OPTION for READLINE so users can disable it for custom builds

PR:		213513
Reported by:	rozhuk.im@gmail.com
MFH:		2017Q1

audio/fluidsynth/Makefile

@@ -3,7 +3,7 @@
 
 PORTNAME=	fluidsynth
 PORTVERSION=	1.1.6
-PORTREVISION=	3
+PORTREVISION=	4
 CATEGORIES=	audio
 MASTER_SITES=	SF/${PORTNAME}/${PORTNAME}-${PORTVERSION}
 
@@ -13,8 +13,9 @@ COMMENT=	Real-time software synthesizer based on the SoundFont 2 specifications
 LICENSE=	LGPL20
 LICENSE_FILE=	${WRKSRC}/COPYING
 
-OPTIONS_DEFINE=	JACK ALSA DBUS LADSPA LASH PORTAUDIO PULSEAUDIO SNDFILE SNDIO
-OPTIONS_DEFAULT=	JACK
+OPTIONS_DEFINE=	JACK ALSA DBUS LADSPA LASH PORTAUDIO PULSEAUDIO READLINE \
+		SNDFILE SNDIO
+OPTIONS_DEFAULT=	JACK READLINE
 
 USE_GNOME=	glib20
 USES=		cmake pkgconfig ninja tar:bzip2
@@ -46,6 +47,9 @@ PORTAUDIO_CMAKE_ON=	-Denable-portaudio:BOOL=TRUE
 PULSEAUDIO_LIB_DEPENDS=	libpulse.so:audio/pulseaudio
 PULSEAUDIO_CMAKE_OFF=	-Denable-pulseaudio:BOOL=FALSE
 
+READLINE_USES=		readline
+READLINE_CMAKE_OFF=	-Denable-readline:BOOL=FALSE
+
 SNDFILE_LIB_DEPENDS=	libsndfile.so:audio/libsndfile
 SNDFILE_CMAKE_OFF=	-Denable-libsndfile:BOOL=FALSE