support building on CentOS 7

builder/Dockerfile

@@ -1,10 +1,15 @@
 ARG base_image
 FROM ${base_image}
 
-RUN yum -y install gcc gcc-c++ make patch git curl && \
+COPY setup_yum_centos7.sh /
+
+# Run twice for EPEL.
+RUN /setup_yum_centos7.sh && \
+    yum -y install gcc gcc-c++ make patch git curl && \
     yum -y install bzip2-devel openssl-devel readline-devel libffi-devel && \
     yum -y install epel-release && \
     yum-config-manager --disable epel && \
+    /setup_yum_centos7.sh && \
     yum -y install --enablerepo=epel openssl11-devel && \
     yum clean all
 

builder/setup_yum_centos7.sh

@@ -0,0 +1,5 @@
+#!/bin/bash -uex
+
+sed -i -E -e 's|^mirrorlist=|#mirrorlist=|g' /etc/yum.repos.d/*.repo
+sed -i -E -e 's|^#(\w*)baseurl=http://mirror.centos.org/centos/(7\|\$releasever)/|baseurl=http://ftp.jaist.ac.jp/pub/Linux/CentOS-vault/7.9.2009/|g' /etc/yum.repos.d/*.repo
+sed -i -E -e 's|^#(\w*)baseurl=http://download.fedoraproject.org/pub/epel/7/|baseurl=http://ftp.jaist.ac.jp/pub/Linux/Fedora/epel/7/|g' /etc/yum.repos.d/*.repo