Use dh-sequence-ppp for building

debian/control

@@ -5,6 +5,7 @@ Standards-Version: 4.5.1
 Vcs-Browser: https://git.in-ulm.de/cbiedl/pptpd
 Vcs-Git: https://git.in-ulm.de/cbiedl/pptpd.git
 Build-Depends: debhelper-compat (= 13),
+    dh-sequence-ppp,
     libwrap0-dev,
     ppp-dev (>= 2.4.7-1+~),
 Priority: optional

debian/rules

@@ -3,7 +3,7 @@
 export DEB_BUILD_MAINT_OPTIONS = hardening=+all
 
 %:
-	dh $@ --with ppp
+	dh $@
 
 override_dh_auto_configure:
 	dh_auto_configure -- \