Use contrib as a single source of truth for nginx/nginx-plus versions.

alpine/Makefile

diff --git a/alpine/Makefile b/alpine/Makefile
index 66debe9..29cf36a 100644
--- a/alpine/Makefile
+++ b/alpine/Makefile
@@ -1,8 +1,13 @@
 SHELL=		/bin/sh
 
-BASE_VERSION=	1.19.6
+CONTRIB?=	../contrib
+CONTRIB:=	$(abspath $(CONTRIB))
+
+include $(CONTRIB)/src/nginx/version
+
+BASE_VERSION=	$(NGINX_VERSION)
 BASE_RELEASE=	1
-PLUS_VERSION=	23
+PLUS_VERSION=	$(NGINX_PLUS_VERSION)
 PLUS_RELEASE=	${BASE_RELEASE}
 BASE_SRC=	nginx-$(BASE_VERSION).tar.gz
 SRCDIR=		nginx-$(BASE_VERSION)
@@ -10,8 +15,6 @@
 DOCS?=		../docs
 SRCPATH?=	../..
 MODSRC_PREFIX=	../
-CONTRIB?=	../contrib
-CONTRIB:=	$(abspath $(CONTRIB))
 
 MODULE_TARGET?= oss
 

contrib/src/nginx/version

diff --git a/contrib/src/nginx/version b/contrib/src/nginx/version
index 3268628..8a82f7c 100644
--- a/contrib/src/nginx/version
+++ b/contrib/src/nginx/version
@@ -1 +1,2 @@
 NGINX_VERSION := 1.19.6
+NGINX_PLUS_VERSION := 23

debian/Makefile

diff --git a/debian/Makefile b/debian/Makefile
index 7d0105f..04f44ad 100644
--- a/debian/Makefile
+++ b/debian/Makefile
@@ -1,16 +1,19 @@
 SHELL=		/bin/bash
 
-BASE_VERSION=	1.19.6
+CONTRIB?=	../contrib
+CONTRIB:=	$(abspath $(CONTRIB))
+
+include $(CONTRIB)/src/nginx/version
+
+BASE_VERSION=	$(NGINX_VERSION)
 BASE_RELEASE=	1
-PLUS_VERSION=	23
+PLUS_VERSION=	$(NGINX_PLUS_VERSION)
 BASE_SRC=	nginx-$(BASE_VERSION).tar.gz
 SRCDIR=		nginx-$(BASE_VERSION)
 SRCPATH?=	../..
 DOCS?=		../docs
 BUILD_ENV_PATH=	${HOME}/debuild
 MODULE_TARGET?=	oss
-CONTRIB?=	../contrib
-CONTRIB:=	$(abspath $(CONTRIB))
 
 ifeq ($(MODULE_TARGET), plus)
 MODULE_CONTROL_TEMPLATE=   nginx-plus-module.control.in

rpm/SPECS/Makefile

diff --git a/rpm/SPECS/Makefile b/rpm/SPECS/Makefile
index 8452a14..465b68c 100644
--- a/rpm/SPECS/Makefile
+++ b/rpm/SPECS/Makefile
@@ -1,8 +1,13 @@
 SHELL=		/bin/bash
 
-BASE_VERSION=	1.19.6
+CONTRIB?=	../../contrib
+CONTRIB:=	$(abspath $(CONTRIB))
+
+include $(CONTRIB)/src/nginx/version
+
+BASE_VERSION=	$(NGINX_VERSION)
 BASE_RELEASE=	1
-PLUS_VERSION=	23
+PLUS_VERSION=	$(NGINX_PLUS_VERSION)
 BASE_SRC=	nginx-$(BASE_VERSION).tar.gz
 SRCPATH?=	../SOURCES
 BUILD_ENV_PATH=	${HOME}/rpmbuild
@@ -10,8 +15,6 @@
 MODSRC_PREFIX=
 BUILD_DIR=	%{bdir}
 DOCS?=		../../docs
-CONTRIB?=	../../contrib
-CONTRIB:=	$(abspath $(CONTRIB))
 
 ifeq ($(MODULE_TARGET), plus)
 MODULE_SPEC_TEMPLATE=	nginx-plus-module.spec.in