title: Fail to install gcc-4.9 in ubuntu17.04
body: <p>While trying to build llvm 3.4 from source on <strong>Ubuntu 17.04</strong>, I have encountered
  some problems related to <strong>gcc 6.3</strong> (described <a href="https://stackoverflow.com/questions/48146921/llvm-3-42-build-from-source-fails-on-ubuntu-17-04">here</a>), so I want to use <strong>gcc-4.9</strong>.
  However, when I run from terminal:</p>
  
  <pre><code>sudo apt install gcc-4.9 --fix-missing
  </code></pre>
  
  <p>I get the following error:</p>
  
  <pre><code>Reading package lists... Done
  Building dependency tree       
  Reading state information... Done
  The following additional packages will be installed:
  cpp-4.9 gcc-4.9-base libasan1 libcloog-isl4 libgcc-4.9-dev
  Suggested packages:
  gcc-4.9-locales gcc-4.9-multilib gcc-4.9-doc libgcc1-dbg libgomp1-dbg libitm1-dbg libatomic1-dbg libasan1-dbg liblsan0-dbg libtsan0-dbg libubsan0-dbg
  libcilkrts5-dbg libquadmath0-dbg
  The following NEW packages will be installed:
  cpp-4.9 gcc-4.9 gcc-4.9-base libasan1 libcloog-isl4 libgcc-4.9-dev
  0 upgraded, 6 newly installed, 0 to remove and 128 not upgraded.
  Need to get 13.2 MB/13.2 MB of archives.
  After this operation, 46.7 MB of additional disk space will be used.
  Do you want to continue? [Y/n] y
  Err:1 http://il.archive.ubuntu.com/ubuntu zesty/universe amd64 gcc-4.9-base amd64 4.9.4-2ubuntu1
  404  Not Found
  Err:2 http://il.archive.ubuntu.com/ubuntu zesty/universe amd64 cpp-4.9 amd64 4.9.4-2ubuntu1
  404  Not Found
  Err:3 http://il.archive.ubuntu.com/ubuntu zesty/universe amd64 libasan1 amd64 4.9.4-2ubuntu1
  404  Not Found
  Err:4 http://il.archive.ubuntu.com/ubuntu zesty/universe amd64 libgcc-4.9-dev amd64 4.9.4-2ubuntu1
  404  Not Found
  Err:5 http://il.archive.ubuntu.com/ubuntu zesty/universe amd64 gcc-4.9 amd64 4.9.4-2ubuntu1
  404  Not Found
  Unable to correct missing packages.
  E: Failed to fetch http://il.archive.ubuntu.com/ubuntu/pool/universe/g/gcc-4.9/gcc-4.9-base_4.9.4-2ubuntu1_amd64.deb  404  Not Found
  E: Failed to fetch http://il.archive.ubuntu.com/ubuntu/pool/universe/g/gcc-4.9/cpp-4.9_4.9.4-2ubuntu1_amd64.deb  404  Not Found
  E: Failed to fetch http://il.archive.ubuntu.com/ubuntu/pool/universe/g/gcc-4.9/libasan1_4.9.4-2ubuntu1_amd64.deb  404  Not Found
  E: Failed to fetch http://il.archive.ubuntu.com/ubuntu/pool/universe/g/gcc-4.9/libgcc-4.9-dev_4.9.4-2ubuntu1_amd64.deb  404  Not Found
  E: Failed to fetch http://il.archive.ubuntu.com/ubuntu/pool/universe/g/gcc-4.9/gcc-4.9_4.9.4-2ubuntu1_amd64.deb  404  Not Found
  E: Aborting install.
  </code></pre>
  
  <p>What is going on here? Thanks!</p>