Add a shared runtime aware host

And use it in dotnet-compile

scripts/docker/Dockerfile

@@ -2,19 +2,32 @@
 FROM debian:jessie
 
 # This could become a "microsoft/coreclr" image, since it just installs the dependencies for CoreCLR (and stdlib)
-# Install CoreCLR dependencies (and clean APT cache)
+# Install CoreCLR dependencies
 RUN apt-get update && \
-    apt-get -qqy install unzip curl libicu-dev libunwind8 gettext libssl-dev libcurl3-gnutls zlib1g && \
-    rm -rf /var/lib/apt/lists/*
+    apt-get -qqy install unzip curl libicu-dev libunwind8 gettext libssl-dev libcurl3-gnutls zlib1g
 
 # No longer need to install DNX since it is embedded (and soon will be gone!)
 
-# Install Package Build Prereqs (and clean up APT cache after to save space in the image)
+# Install Build Prereqs
 RUN echo "deb http://llvm.org/apt/trusty/ llvm-toolchain-trusty-3.6 main" | tee /etc/apt/sources.list.d/llvm.list && \
     curl http://llvm.org/apt/llvm-snapshot.gpg.key | apt-key add - && \
     apt-get update && \
-    apt-get install -y debhelper build-essential devscripts git liblttng-ust-dev lldb-3.6-dev && \
-    rm -rf /var/lib/apt/lists/*
+    apt-get install -y debhelper build-essential devscripts git liblttng-ust-dev lldb-3.6-dev lldb-3.6 clang
+
+# Install latest cmake
+RUN mkdir -p /opt/src/cmake && \
+    cd /opt/src/cmake && \
+    curl -O https://cmake.org/files/v3.4/cmake-3.4.0-rc2.tar.gz && \
+    tar xzf cmake-3.4.0-rc2.tar.gz && \
+    cd cmake-3.4.0-rc2 && \
+    ./bootstrap && \
+    make && \
+    make install && \
+    cd /opt && \
+    rm -Rf /opt/src/cmake
+
+# Use clang as c++ compiler
+RUN update-alternatives --set c++ /usr/bin/clang++
 
 # Set working directory
 WORKDIR /opt/code