diff --git a/devel/mdb/Makefile b/devel/mdb/Makefile
index 862f8b0691d3..25764650c01a 100644
--- a/devel/mdb/Makefile
+++ b/devel/mdb/Makefile
@@ -1,45 +1,46 @@
 PORTNAME=	mdb
 PORTVERSION=	20210125
+PORTREVISION=	1
 CATEGORIES=	devel
 
 MAINTAINER=	jhb@FreeBSD.org
 COMMENT=	Solaris Modular Debugger
 
 LICENSE=	CDDL
 
 USES=		compiler uidfix
 
 USE_GITHUB=	yes
 GH_ACCOUNT=	bsdjhb
 GH_PROJECT=	illumos-gate
 GH_TAGNAME=	60ff9f11c2
 
 ONLY_FOR_ARCHS=	amd64
 
 MAKE_ARGS=	WITH_CTF=yes
 MAKE_ARGS+=	BINDIR=${PREFIX}/bin
 MAKE_ARGS+=	LIBDIR=${PREFIX}/lib
 MAKE_ARGS+=	FREEBSD_SRC_DIR=${SRC_BASE}
 MAKE_ARGS+=	STRIP=
 WRKSRC_SUBDIR=	freebsd/cddl/usr.bin/mdb
 CFLAGS+=	-DMDB_PREFIX=\\\"${PREFIX}\\\" -g
 
 .include <bsd.port.pre.mk>
 
 .if !exists(${SRC_BASE}/cddl/compat) || !exists(${SRC_BASE}/sys/cddl/compat)
 IGNORE=		requires full source tree with CDDL sources
 .endif
 
 .if ${OSVERSION} < 1300015 && ${COMPILER_TYPE} == "clang" && \
     ${COMPILER_VERSION} >= 80
 # clang 8 cannot compile due to enum redefinitions in kernel.h
 BUILD_DEPENDS+=	${LOCALBASE}/bin/clang70:devel/llvm70
 CPP=	${LOCALBASE}/bin/clang-cpp70
 CC=	${LOCALBASE}/bin/clang70
 CXX=	${LOCALBASE}/bin/clang++70
 .endif
 
 pre-install:
 	${MKDIR} ${STAGEDIR}${PREFIX}/lib/mdb/kvm/${MACHINE_ARCH}
 
 .include <bsd.port.post.mk>
diff --git a/devel/mdb/files/patch-mdb_Makefile b/devel/mdb/files/patch-mdb_Makefile
new file mode 100644
index 000000000000..2258d0c3ba9b
--- /dev/null
+++ b/devel/mdb/files/patch-mdb_Makefile
@@ -0,0 +1,11 @@
+--- mdb/Makefile.orig	2021-01-25 20:32:57 UTC
++++ mdb/Makefile
+@@ -201,7 +201,7 @@ CWARNFLAGS.clang+= \
+ 	-Wno-shadow \
+ 	-Wno-sign-compare \
+ 	-Wno-strict-prototypes \
+-	-Wno-error-tautological-pointer-compare \
++	-Wno-error=tautological-pointer-compare \
+ 	-Wno-unused-parameter
+ 
+ .if ${COMPILER_TYPE} == "clang" && ${COMPILER_VERSION} >= 100000 || \