diff --git a/devel/muon/Makefile b/devel/muon/Makefile
index 8d87f89611ce..b4c2c66cf162 100644
--- a/devel/muon/Makefile
+++ b/devel/muon/Makefile
@@ -1,37 +1,40 @@
 PORTNAME=	muon
-DISTVERSION=	0.2.0
+DISTVERSION=	0.3.1
 CATEGORIES=	devel
 MASTER_SITES=	https://git.sr.ht/~lattis/${PORTNAME}/archive/${DISTVERSIONFULL}${EXTRACT_SUFX}?dummy=/
 
 MAINTAINER=	bapt@FreeBSD.org
 COMMENT=	Build system compatible with meson
 WWW=		https://muon.build/
 
 LICENSE=	GPLv3
 LICENSE_FILE=	${WRKSRC}/LICENSES/GPL-3.0-only.txt
 
 BUILD_DEPENDS=	scdoc:textproc/scdoc
 
 USES=		ninja pkgconfig:both
 
 BUILD_WRKSRC=	${WRKSRC}/_build
 INSTALL_WRKSRC=	${WRKSRC}/_build
 
 ALL_TARGET=
 PLIST_FILES=	bin/muon \
 		share/man/man1/muon.1.gz \
 		share/man/man5/meson.build.5.gz
+USE_CSTD=	c99
+CFLAGS+=	-D__XSI_VISIBLE=1
+CONFIGURE_ENV=	CC="${CC}" CFLAGS="${CFLAGS}"
 
 post-patch:
 # this confuses some of the FreeBSD configure targets
 	@${RM} -r ${WRKSRC}/tests/project/common
 
 do-configure:
 	@(cd ${WRKSRC} && \
-		${SH} bootstrap.sh . && \
+		${SETENV} ${CONFIGURE_ENV} ${SH} bootstrap.sh . && \
 		./muon setup -Dlibcurl=disabled -Dlibarchive=disabled ${BUILD_WRKSRC})
 
 do-install:
 	@(${SETENV} ${MAKE_ENV} ${BUILD_WRKSRC}/muon -C ${BUILD_WRKSRC} install)
 
 .include <bsd.port.mk>
diff --git a/devel/muon/distinfo b/devel/muon/distinfo
index 7c12c8f8a1d9..1d5d3dc08502 100644
--- a/devel/muon/distinfo
+++ b/devel/muon/distinfo
@@ -1,3 +1,3 @@
-TIMESTAMP = 1694768682
-SHA256 (muon-0.2.0.tar.gz) = d73db1be5388821179a25a15ba76fd59a8bf7c8709347a4ec2cb91755203f36c
-SIZE (muon-0.2.0.tar.gz) = 510533
+TIMESTAMP = 1731066215
+SHA256 (muon-0.3.1.tar.gz) = 14b175b29c4390a69c1d9b5758b4689f0456c749822476af67511f007be2e503
+SIZE (muon-0.3.1.tar.gz) = 446185