AWS Codebuild: avoid one round of apt-get update

Author: Daniel Kroening

buildspec.yml

@@ -3,9 +3,7 @@ version: 0.2
 phases:
   install:
     commands:
-      - apt-get update -y
-      - apt-get install -y software-properties-common
-      - add-apt-repository -y ppa:ubuntu-toolchain-r/test
+      - echo "deb http://ppa.launchpad.net/ubuntu-toolchain-r/test/ubuntu trusty main" > /etc/apt/sources.list.d/01-toolchain
       - apt-get update -y
       - apt-get install -y g++-5 flex bison make git libwww-perl patch ccache
       - apt-get install -y openjdk-7-jdk