Move common parts out from this project

Author: Marek Skalický

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "common"]
+	path = common
+	url = https://github.com/sclorg/container-common-scripts.git

Makefile

@@ -1,7 +1,10 @@
-# Variables are documented in hack/build.sh.
+# Variables are documented in common/build.sh.
 BASE_IMAGE_NAME = perl
 VERSIONS = 5.20 5.24
 OPENSHIFT_NAMESPACES = 5.16
 
-# Include common Makefile code.
-include hack/common.mk
+# HACK:  Ensure that 'git pull' for old clones doesn't cause confusion.
+# New clones should use '--recursive'.
+.PHONY: $(shell test -f common/common.mk || echo >&2 'Please do "git submodule update --init" first.')
+
+include common/common.mk

README.md

@@ -32,7 +32,7 @@ To build a Perl image, choose either the CentOS or RHEL based image:
     subscribed RHEL machine.
 
     ```
-    $ git clone https://github.com/openshift/s2i-perl.git
+    $ git clone --recursive https://github.com/openshift/s2i-perl.git
     $ cd s2i-perl
     $ make build TARGET=rhel7 VERSION=5.24
     ```
@@ -48,7 +48,7 @@ To build a Perl image, choose either the CentOS or RHEL based image:
     To build the perl-5.24 image from scratch run:
 
     ```
-    $ git clone https://github.com/openshift/s2i-perl.git
+    $ git clone --recursive https://github.com/openshift/s2i-perl.git
     $ cd s2i-perl
     $ make build TARGET=centos7 VERSION=5.24
     ```