Add 'unzip' to Ubuntu required packages.
diff --git a/README b/README
index 829ecec..9f61021 100644
--- a/README
+++ b/README
@@ -11,7 +11,7 @@
1. Install Ubuntu 14.04 or Debian 7.5 64-bit.
2. Install the packages necessary for the build:
> sudo apt-get install cscope ctags libz-dev libexpat-dev libc6-dev-i386 \
- build-essential g++ git bison flex gcc-multilib g++-multilib \
+ build-essential g++ git bison flex gcc-multilib g++-multilib unzip \
libxml-simple-perl libxml-sax-perl libxml2-dev libxml2-utils xsltproc
3. Continue with the clone, environment setup, and build as noted above.