Allow to build either with python2 or python3 so that package can be built anywhere

WARNING: Do not use PYTHON make variable since it messes up with compilation. Instead
use SLAPOS_BOOTSTRAP_SYSTEM_PYTHON which explains the idea of the variable
and does not overrides make's PYTHON variable in other places.

obs/slapos/debian/control

@@ -4,7 +4,7 @@ Section: net
 Priority: optional
 Build-Depends: debhelper,
                chrpath,
-               python3
+               python3 (>=3.7) | python
 Homepage: https://slapos.nexedi.com
 
 Package: slapos-node

obs/slapos/slapos-node/Makefile

@@ -2,12 +2,12 @@
 # -*- makefile -*-
 
 build: 
-	cd slapos; make build PYTHON=python3
+	make -C slapos build SLAPOS_BOOTSTRAP_SYSTEM_PYTHON=$(shell which python2.7 2> /dev/null || echo python3)
 
 all: build
 
 install: all
-	cd slapos; make install
+	make -C slapos install
 	mkdir -p $(DESTDIR)/usr/bin/
 	mkdir -p $(DESTDIR)/usr/sbin/
 	sed -i "s/\/opt\/slapos\/rebootstrap\/parts/\/opt\/slapos\/parts/g" $(DESTDIR)/opt/slapos/bin/*

obs/slapos/templates/Makefile.in

@@ -4,7 +4,6 @@
 VERSION = %VERSION%
 RECIPE_VERSION = %RECIPE_VERSION%
 
-PY = $(PYTHON)
 INSTALL_DIRECTORY = $(DESTDIR)/opt/slapos
 TARGET_DIRECTORY = /opt/slapos
 BUILD_ROOT_DIRECTORY := $(shell pwd)/build
@@ -24,11 +23,11 @@ build-stamp:
 
 	@echo "Bootstrapping buildout"
 	cd $(BUILD_DIRECTORY) && \
-		$(PY) ./bootstrap
+		$(SLAPOS_BOOTSTRAP_SYSTEM_PYTHON) ./bootstrap
 
 	@echo 'Preparing source tarball (recipe version: $(RECIPE_VERSION))'
 	cd $(BUILD_DIRECTORY) && \
-		$(PY) ./bin/buildout -v
+		$(SLAPOS_BOOTSTRAP_SYSTEM_PYTHON) ./bin/buildout -v
 
 	@touch build-stamp
 

obs/slapos/templates/PKGBUILD.in

-# Maintainer: Rafael Monnerat <rafael@nexedi.com>
+# Maintainer: Thomas Gambier <thomas.gambier@nexedi.com>
 pkgname=slapos-node
 pkgver=%VERSION%+%RECIPE_VERSION%+%RELEASE%
 pkgdesc="Slapos node"
@@ -6,15 +6,15 @@ pkgrel=1
 arch=('x86_64' 'i686')
 url="http://www.slapos.org"
 license=('GPL')
-depends=(python3 python3-distribute iptables iproute2)
-makedepends=(patch wget chrpath inetutils)
+depends=(iptables iproute2)
+makedepends=(patch wget chrpath inetutils python3)
 install='slapos-node.install'
 source=(${pkgname}_${pkgver}.tar.gz)
 md5sums=(%SOURCEMD5%)
 
 build() {
 	cd "${srcdir}/${pkgname}_${pkgver}"
-	make PYTHON=python3
+	make
 }
 
 package() {

obs/slapos/templates/slapos.dsc.in

@@ -3,10 +3,10 @@ Source: slapos-node
 Binary: slapos-node
 Architecture: any
 Version: %VERSION%+%RECIPE_VERSION%+%RELEASE%-1
-Maintainer: Rafael Monnerat <rafael@nexedi.com>
-Homepage: http://community.slapos.org
+Maintainer: Thomas Gambier <thomas.gambier@nexedi.com>
+Homepage: http://slapos.nexedi.com
 Standards-Version: 3.9.2
-Build-Depends: debhelper (>= 4.1.16), chrpath, po-debconf, wget, python3, python3-dev, libssl-dev
+Build-Depends: debhelper (>= 4.1.16), chrpath, po-debconf, wget, python3 (>= 3.7) | python, python3-dev (>= 3.7) | python-dev, libssl-dev
 Files: 
  1c2803e4693c74042985d753c9c3ba53 73736102 slapos-node_%VERSION%+%RECIPE_VERSION%+%RELEASE%.orig.tar.gz
  1c2803e4693c74042985d753c9c3ba53 6102 slapos-node_%VERSION%+%RECIPE_VERSION%+%RELEASE%-1.diff.tar.gz

obs/slapos/templates/slapos.spec.in

@@ -44,11 +44,22 @@ Group: Application/Network
 Source0: slapos-node_%{unmangled_version}+%{slapversion}+%{release_number}.tar.gz
 URL: http://community.slapos.org/ 
 Vendor: Vifib
-Packager: Rafael Monnerat <rafael@nexedi.com>
-
-BuildRequires: gcc-c++, make, patch, wget, python3, chrpath, openssl-devel
-
-Requires: bridge-utils, gcc-c++, make, patch, wget, lm_sensors
+Packager: Thomas Gambier <thomas.gambier@nexedi.com>
+
+BuildRequires: gcc-c++
+BuildRequires: make
+BuildRequires: patch
+BuildRequires: wget
+BuildRequires: chrpath
+BuildRequires: openssl-devel
+%if 0%{?centos_version} <= 700 || 0%{?rhel_version} <= 700 || 0%{?suse_version} < 1300 || 0%{?sle_version} < 130000
+BuildRequires: python
+BuildRequires: python-devel
+%else
+BuildRequires: python3
+BuildRequires: python3-devel
+%endif
+Requires: gcc-c++, make, patch, wget, lm_sensors
 
 AutoReqProv: no
 
@@ -77,7 +88,7 @@ zcat $RPM_SOURCE_DIR/slapos-node_%{unmangled_version}+%{slapversion}+%{release_n
 
 %build
 cd $RPM_BUILD_DIR/slapos-node_%{unmangled_version}+%{slapversion}+%{release_number}
-make PYTHON=python3
+make
 
 %install
 cd $RPM_BUILD_DIR/slapos-node_%{unmangled_version}+%{slapversion}+%{release_number}/