ENH: Compile git with SSL support

Older versions of git included in older linux distributions are not able
to download source from Github. A newer version is required with a newer
OpenSSL. This requires to also build curl with the same OpenSSL.

CMake is downloaded precompiled if available (64bits system) or compiled
from source otherwise.

imagefiles/build-and-install-openssl.sh

@@ -0,0 +1,81 @@
+#!/bin/bash
+#
+# Configure, build and install OpenSSL
+#
+# Usage:
+#
+#  build-and-install-openssl.sh [-32]
+#
+# Options:
+#
+#  -32              Build OpenSSL as a 32-bit library
+#
+# Notes:
+#
+#  * build directory is /usr/src/openssl-$OPENSSL_VERSION
+#
+#  * install directory is /usr
+#
+#  * after installation, build directory and archive are removed
+#
+
+set -ex
+set -o pipefail
+
+WRAPPER=""
+CONFIG_FLAG="-fPIC"
+
+while [ $# -gt 0 ]; do
+  case "$1" in
+    -32)
+      WRAPPER="linux32"
+      CONFIG_FLAG="-m32"
+      ;;
+    *)
+      echo "Usage: Usage: ${0##*/} [-32]"
+      exit 1
+      ;;
+  esac
+  shift
+done
+
+MY_DIR=$(dirname "${BASH_SOURCE[0]}")
+source $MY_DIR/utils.sh
+
+#
+# Function 'do_openssl_build' and 'build_openssl'
+# copied from https://github.com/pypa/manylinux/tree/master/docker/build_scripts
+#
+
+OPENSSL_ROOT=openssl-1.0.2o
+# Hash from https://www.openssl.org/source/openssl-1.0.2o.tar.gz.sha256
+# Matches hash at https://github.com/Homebrew/homebrew-core/blob/1766321103d9780f6e38d3ac7681b8fa42cdca86/Formula/openssl.rb#L11
+OPENSSL_HASH=ec3f5c9714ba0fd45cb4e087301eb1336c317e0d20b575a125050470e8089e4d
+
+# XXX: the official https server at www.openssl.org cannot be reached
+# with the old versions of openssl and curl in Centos 5.11 hence the fallback
+# to the ftp mirror:
+OPENSSL_DOWNLOAD_URL=ftp://ftp.openssl.org/source
+
+function do_openssl_build {
+    ${WRAPPER} ./config no-ssl2 no-shared -fPIC $CONFIG_FLAG --prefix=/usr/local/ssl > /dev/null
+    ${WRAPPER} make > /dev/null
+    ${WRAPPER} make install_sw > /dev/null
+}
+
+function build_openssl {
+    local openssl_fname=$1
+    check_var ${openssl_fname}
+    local openssl_sha256=$2
+    check_var ${openssl_sha256}
+    check_var ${OPENSSL_DOWNLOAD_URL}
+    # Can't use curl here because we don't have it yet
+    curl -# -LO ${OPENSSL_DOWNLOAD_URL}/${openssl_fname}.tar.gz
+    check_sha256sum ${openssl_fname}.tar.gz ${openssl_sha256}
+    tar -xzf ${openssl_fname}.tar.gz
+    (cd ${openssl_fname} && do_openssl_build)
+    rm -rf ${openssl_fname} ${openssl_fname}.tar.gz /usr/ssl/man
+}
+
+cd /usr/src
+build_openssl $OPENSSL_ROOT $OPENSSL_HASH