diff --git a/audio/libremidi/Makefile b/audio/libremidi/Makefile
index 53ee1f93ba86..1e609df4769e 100644
--- a/audio/libremidi/Makefile
+++ b/audio/libremidi/Makefile
@@ -1,43 +1,43 @@
 PORTNAME=	libremidi
 DISTVERSIONPREFIX=	v
 DISTVERSION=	4.5.0
 CATEGORIES=	audio
 
 MAINTAINER=	yuri@FreeBSD.org
 COMMENT=	Modern C++ MIDI real-time & file I/O library
 WWW=		https://github.com/jcelerier/libremidi
 
 LICENSE=	BSD2CLAUSE
 LICENSE_FILE=	${WRKSRC}/LICENSE.md
 
 TEST_DEPENDS=	catch2>0:devel/catch2
 
 USES=		cmake:testing compiler:c++20-lang localbase
 
 USE_GITHUB=	yes
 GH_ACCOUNT=	jcelerier
 
 CMAKE_ON=	BUILD_SHARED_LIBS
 CMAKE_OFF=	LIBREMIDI_TESTS
 CMAKE_ARGS=	-DFETCHCONTENT_TRY_FIND_PACKAGE_MODE=ALWAYS
 CMAKE_TESTING_ON=	LIBREMIDI_TESTS
 
 OPTIONS_DEFINE=		JACK
 OPTIONS_DEFAULT=	JACK
 
 .if exists(/usr/include/sys/eventfd.h) && exists(/usr/include/sys/timerfd.h)
 OPTIONS_DEFINE+=	ALSA
 OPTIONS_DEFAULT+=	ALSA # ALSA support requires libalsa, sys/eventfd.h, sys/timerfd.h
 
 ALSA_CMAKE_OFF=		-DLIBREMIDI_NO_ALSA=ON
 ALSA_LIB_DEPENDS=	libasound.so:audio/alsa-lib
 .else
-CMAKE_ON=		LIBREMIDI_NO_ALSA
+CMAKE_ON+=		LIBREMIDI_NO_ALSA
 .endif
 
 JACK_CMAKE_OFF=		-DLIBREMIDI_NO_JACK=ON
 JACK_LIB_DEPENDS=	libjack.so:audio/jack
 
 # This library can also be used as a header-only library
 
 .include <bsd.port.mk>