Index: Mk/bsd.port.mk
===================================================================
--- Mk/bsd.port.mk
+++ Mk/bsd.port.mk
@@ -2051,6 +2051,14 @@
 
 DISTINFO_FILE?=		${MASTERDIR}/distinfo
 
+# Timestamp for package archive metadata, for reproducible builds, with a
+# default for ports that do not override it via distinfo.
+TIMESTAMP=			1500000000
+.if !make(*depends*) && empty(.MAKEFLAGS:M-V) && \
+    empty(.MAKEFLAGS:MTIMESTAMP) && exists(${DISTINFO_FILE})
+TIMESTAMP!= ${AWK} -F' = ' -v ts=${TIMESTAMP} '/^TIMESTAMP/ { ts=$$2 } END { print ts}' ${DISTINFO_FILE}
+.endif
+
 MAKE_FLAGS?=	-f
 MAKEFILE?=		Makefile
 MAKE_CMD?=		${BSDMAKE}
@@ -2062,6 +2070,9 @@
 			LDFLAGS="${LDFLAGS}" LIBS="${LIBS}" \
 			CXX="${CXX}" CXXFLAGS="${CXXFLAGS}" \
 			MANPREFIX="${MANPREFIX}"
+.if empty(USES:Mpython*)
+PKG_ENV+=	SOURCE_DATE_EPOCH=${TIMESTAMP}
+.endif
 
 # Add -fno-strict-aliasing to CFLAGS with optimization level -O2 or higher.
 # gcc 4.x enable strict aliasing optimization with -O2 which is known to break