BUILD: extend travis-ci matrix

added openssl-1.0.2, 1.1.0, 1.1.1, libressl-2.7.5, 2.8.3, 2.9.1
added linux-ppc64le image

scripts/build-ssl.sh

@@ -0,0 +1,77 @@
+#!/bin/sh
+set -eux
+
+download_openssl () {
+    if [ ! -f "download-cache/openssl-${OPENSSL_VERSION}.tar.gz" ]; then
+        wget -P download-cache/ \
+            "https://www.openssl.org/source/openssl-${OPENSSL_VERSION}.tar.gz"
+    fi
+}
+
+build_openssl_linux () {
+    (
+        cd "openssl-${OPENSSL_VERSION}/"
+        ./config shared --prefix="${HOME}/opt" --openssldir="${HOME}/opt" -DPURIFY
+        make all install_sw
+    )
+}
+
+build_openssl_osx () {
+    (
+        cd "openssl-${OPENSSL_VERSION}/"
+        ./Configure darwin64-x86_64-cc shared \
+            --prefix="${HOME}/opt" --openssldir="${HOME}/opt" -DPURIFY
+        make depend all install_sw
+    )
+}
+
+build_openssl () {
+    if [ "$(cat ${HOME}/opt/.openssl-version)" != "${OPENSSL_VERSION}" ]; then
+        tar zxf "download-cache/openssl-${OPENSSL_VERSION}.tar.gz"
+        if [ "${TRAVIS_OS_NAME}" = "osx" ]; then
+            build_openssl_osx
+        elif [ "${TRAVIS_OS_NAME}" = "linux" ]; then
+            build_openssl_linux
+        fi
+        echo "${OPENSSL_VERSION}" > "${HOME}/opt/.openssl-version"
+    fi
+}
+
+download_libressl () {
+    if [ ! -f "download-cache/libressl-${LIBRESSL_VERSION}.tar.gz" ]; then
+        wget -P download-cache/ \
+	    "https://ftp.openbsd.org/pub/OpenBSD/LibreSSL/libressl-${LIBRESSL_VERSION}.tar.gz"
+    fi
+}
+
+build_libressl() {
+    (
+        cd "libressl-${LIBRESSL_VERSION}/"
+        ./configure --prefix="${HOME}/opt"
+        make all install
+    )
+}
+
+build_libressl () {
+    if [ "$(cat ${HOME}/opt/.libressl-version)" != "${LIBRESSL_VERSION}" ]; then
+        tar zxf "download-cache/libressl-${LIBRESSL_VERSION}.tar.gz"
+        (
+           cd "libressl-${LIBRESSL_VERSION}/"
+           ./configure --prefix="${HOME}/opt"
+            make all install
+        )
+        echo "${LIBRESSL_VERSION}" > "${HOME}/opt/.libressl-version"
+    fi
+}
+
+if [ ! -z ${LIBRESSL_VERSION+x} ]; then
+	download_libressl
+	build_libressl
+fi
+
+if [ ! -z ${OPENSSL_VERSION+x} ]; then
+	download_openssl
+	build_openssl
+fi
+
+