Update glibc to 2.27-r0

Dockerfile

@@ -17,15 +17,18 @@ MAINTAINER Tom Denham <[email protected]>
 # Set the minimum Docker API version required for libnetwork.
 ENV DOCKER_API_VERSION 1.21
 
+# Set glibc version
+ENV GLIBC_VERSION 2.27-r0
+
 # Download and install glibc for use by non-static binaries that require it.
 RUN apk --no-cache add wget ca-certificates libgcc && \
     wget -q -O /etc/apk/keys/sgerrand.rsa.pub https://raw.githubusercontent.com/sgerrand/alpine-pkg-glibc/master/sgerrand.rsa.pub && \
-    wget https://github.com/sgerrand/alpine-pkg-glibc/releases/download/2.23-r3/glibc-2.23-r3.apk && \
-    wget https://github.com/sgerrand/alpine-pkg-glibc/releases/download/2.23-r3/glibc-bin-2.23-r3.apk && \
-    apk add glibc-2.23-r3.apk glibc-bin-2.23-r3.apk && \
+    wget https://github.com/sgerrand/alpine-pkg-glibc/releases/download/$GLIBC_VERSION/glibc-$GLIBC_VERSION.apk && \
+    wget https://github.com/sgerrand/alpine-pkg-glibc/releases/download/$GLIBC_VERSION/glibc-bin-$GLIBC_VERSION.apk && \
+    apk add glibc-$GLIBC_VERSION.apk glibc-bin-$GLIBC_VERSION.apk && \
     /usr/glibc-compat/sbin/ldconfig /lib /usr/glibc/usr/lib && \
     apk del wget && \
-    rm -f glibc-2.23-r3.apk glibc-bin-2.23-r3.apk
+    rm -f glibc-$GLIBC_VERSION.apk glibc-bin-$GLIBC_VERSION.apk
 
 # Install runit from the community repository, as its not yet available in global
 RUN apk add --no-cache --repository "http://alpine.gliderlabs.com/alpine/edge/community" runit