Fixed gcc-6 dependency by adding libmpx2 (#1492)

Author: thom-sd

docker/dev/Dockerfile

@@ -32,6 +32,7 @@ RUN apt-get update \
 	llvm-7 \
 	procps \
 	xz-utils \
+	libmpx2 \
  && rm -rf /var/lib/apt/lists/*
 
 # gcc 6 is no longer included in debian unstable, but we need it to

docker/local/Dockerfile

@@ -32,6 +32,7 @@ RUN apt-get update \
 	llvm-7 \
 	procps \
 	xz-utils \
+	libmpx2 \
  && rm -rf /var/lib/apt/lists/*
 
 # gcc 6 is no longer included in debian unstable, but we need it to

docker/stable/Dockerfile

@@ -32,6 +32,7 @@ RUN apt-get update \
 	llvm-7 \
 	procps \
 	xz-utils \
+	libmpx2 \
  && rm -rf /var/lib/apt/lists/*
 
 # gcc 6 is no longer included in debian unstable, but we need it to