Merge pull request AdoptOpenJDK#70 from moritzraho/master

 alpine: verified download + fixed version for zlib, gcc-libs and glibc

Author: Dinakar Guniguntala

dockerfile_functions.sh

@@ -87,16 +87,23 @@ print_alpine_pkg() {
 	cat >> $1 <<'EOI'
 
 RUN apk --update add --no-cache ca-certificates curl openssl binutils xz \
-    && GLIBC_VER="2.25-r0" \
+    && GLIBC_VER="2.28-r0" \
     && ALPINE_GLIBC_REPO="https://github.com/sgerrand/alpine-pkg-glibc/releases/download" \
+    && GCC_LIBS_URL="https://archive.archlinux.org/packages/g/gcc-libs/gcc-libs-8.2.1%2B20180831-1-x86_64.pkg.tar.xz" \
+    && GCC_LIBS_SHA256=e4b39fb1f5957c5aab5c2ce0c46e03d30426f3b94b9992b009d417ff2d56af4d \
+    && ZLIB_URL="https://archive.archlinux.org/packages/z/zlib/zlib-1%3A1.2.9-1-x86_64.pkg.tar.xz" \
+    && ZLIB_SHA256=bb0959c08c1735de27abf01440a6f8a17c5c51e61c3b4c707e988c906d3b7f67 \
+    && curl -Ls https://alpine-pkgs.sgerrand.com/sgerrand.rsa.pub -o /etc/apk/keys/sgerrand.rsa.pub \
     && curl -Ls ${ALPINE_GLIBC_REPO}/${GLIBC_VER}/glibc-${GLIBC_VER}.apk > /tmp/${GLIBC_VER}.apk \
-    && apk add --allow-untrusted /tmp/${GLIBC_VER}.apk \
-    && curl -Ls https://www.archlinux.org/packages/core/x86_64/gcc-libs/download > /tmp/gcc-libs.tar.xz \
+    && apk add /tmp/${GLIBC_VER}.apk \
+    && curl -Ls ${GCC_LIBS_URL} -o /tmp/gcc-libs.tar.xz \
+    && echo "${GCC_LIBS_SHA256}  /tmp/gcc-libs.tar.xz" | sha256sum -c - \
     && mkdir /tmp/gcc \
     && tar -xf /tmp/gcc-libs.tar.xz -C /tmp/gcc \
     && mv /tmp/gcc/usr/lib/libgcc* /tmp/gcc/usr/lib/libstdc++* /usr/glibc-compat/lib \
     && strip /usr/glibc-compat/lib/libgcc_s.so.* /usr/glibc-compat/lib/libstdc++.so* \
-    && curl -Ls https://www.archlinux.org/packages/core/x86_64/zlib/download > /tmp/libz.tar.xz \
+    && curl -Ls ${ZLIB_URL} -o /tmp/libz.tar.xz \
+    && echo "${ZLIB_SHA256}  /tmp/libz.tar.xz" | sha256sum -c - \
     && mkdir /tmp/libz \
     && tar -xf /tmp/libz.tar.xz -C /tmp/libz \
     && mv /tmp/libz/usr/lib/libz.so* /usr/glibc-compat/lib \