diff -Nru varnish-6.4.0/debian/changelog varnish-6.4.0/debian/changelog
--- varnish-6.4.0/debian/changelog	2020-04-23 10:06:04.000000000 +0000
+++ varnish-6.4.0/debian/changelog	2020-05-24 17:11:49.000000000 +0000
@@ -1,3 +1,13 @@
+varnish (6.4.0-3) unstable; urgency=medium
+
+  [ Stig Sandbeck Mathisen ]
+  * Work around a breaking change in GNU make 4.3
+
+  [ Clint Adams ]
+  * Use mktemp instead of tempfile (Closes: #961392)
+
+ -- Stig Sandbeck Mathisen <ssm@debian.org>  Sun, 24 May 2020 19:11:49 +0200
+
 varnish (6.4.0-2) unstable; urgency=medium
 
   * Bump packaging version for source only upload. No other changes.
diff -Nru varnish-6.4.0/debian/rules varnish-6.4.0/debian/rules
--- varnish-6.4.0/debian/rules	2020-04-23 10:06:04.000000000 +0000
+++ varnish-6.4.0/debian/rules	2020-05-24 17:11:49.000000000 +0000
@@ -13,16 +13,19 @@
 # Set local state dir for FHS
 LOCAL_CONFIGURE_FLAGS = --localstatedir=/var/lib
 
+# Workaround for a breaking change in GNU make 4.3.
+H := \#
+
 # Extract VMOD_ABI version, this is used for building vmods using the official
 # VMOD API
-VMOD_ABI = $(shell printf '\#include "vrt.h"\nvarnishabi- VRT_MAJOR_VERSION . VRT_MINOR_VERSION\n' \
+VMOD_ABI = $(shell printf '$(H)include "vdef.h"\n$(H)include "vrt.h"\nvarnishabi- VRT_MAJOR_VERSION . VRT_MINOR_VERSION\n' \
 	   | cpp - -Iinclude \
 	   | sed -e '/^varnishabi-/!d' -e 's/U//g' -e 's/ //g')
 
 # Extract VMOD_strictABI, which refers to the exact build of varnish. This is
 # used for old style vmods bypassing the VMOD API, accessing the internal data
 # structures directly.
-VMOD_strictABI = $(shell printf '\#include "vcs_version.h"\nVCS_Version\n' \
+VMOD_strictABI = $(shell printf '$(H)include "vcs_version.h"\nVCS_Version\n' \
 		 | cpp - -Iinclude \
 		 | sed -e '/^"/!d' -e 's/\"//g' -e 's/^/varnishabi-strict-/')
 
diff -Nru varnish-6.4.0/debian/varnish.init varnish-6.4.0/debian/varnish.init
--- varnish-6.4.0/debian/varnish.init	2020-04-23 10:06:04.000000000 +0000
+++ varnish-6.4.0/debian/varnish.init	2020-05-24 17:11:49.000000000 +0000
@@ -45,7 +45,7 @@
 
 start_varnishd() {
     log_daemon_msg "Starting $DESC" "$NAME"
-    output=$(/bin/tempfile -s.varnish)
+    output=$(mktemp --suffix=.varnish)
     if start-stop-daemon \
         --start --quiet --pidfile ${PIDFILE} --exec ${DAEMON} -- \
         -P ${PIDFILE} ${DAEMON_OPTS} > ${output} 2>&1; then
diff -Nru varnish-6.4.0/debian/varnish.varnishncsa.init varnish-6.4.0/debian/varnish.varnishncsa.init
--- varnish-6.4.0/debian/varnish.varnishncsa.init	2020-04-23 10:06:04.000000000 +0000
+++ varnish-6.4.0/debian/varnish.varnishncsa.init	2020-05-24 17:11:49.000000000 +0000
@@ -37,7 +37,7 @@
 test -x $DAEMON || exit 0
 
 start_varnishncsa() {
-    output=$(/bin/tempfile -s.varnish)
+    output=$(mktemp --suffix=.varnish)
     log_daemon_msg "Starting $DESC" "$NAME"
     create_pid_directory
     if start-stop-daemon --start --quiet --pidfile ${PIDFILE} \