Download Clang from SourceMod site (#523)

Also switch to Clang 3.8

.travis.yml

@@ -1,15 +1,13 @@
 addons:
   apt:
     packages:
-    - clang-3.7
     - lib32stdc++6
     - lib32z1-dev
     - libc6-dev-i386
     - linux-libc-dev
     - g++-multilib
-    - g++4.8
+    - g++-4.8
     sources:
-    - llvm-toolchain-precise-3.7
     - ubuntu-toolchain-r-test
   cache:
     directories:
@@ -18,10 +16,18 @@ language: cpp
 sudo: false
 compiler:
   - clang
+env:
+  global:
+  - LLVM_ARCHIVE_URI=http://sourcemod.net/clang+llvm-3.8.0-x86_64-linux-gnu-ubuntu-14.04.tar.xz
+before_install:
+  - wget -nc $LLVM_ARCHIVE_URI -O $HOME/clang+llvm.tar.xz
+  - mkdir -p $HOME/clang+llvm
+  - tar -xf $HOME/clang+llvm.tar.xz -C $HOME/clang+llvm --strip-components 1
+  - export PATH=$HOME/clang+llvm/bin:$PATH
 before_script:
   - CHECKOUT_DIR=$PWD && cd .. && $CHECKOUT_DIR/tools/checkout-deps.sh && cd $CHECKOUT_DIR
 script:
   - mkdir build && cd build
   - PATH="~/.local/bin:$PATH"
-  - CC=clang-3.7 CXX=clang-3.7 python ../configure.py --enable-optimize --sdks=episode1,tf2,l4d2,csgo,dota
-  - ambuild
+  - CC=clang-3.8 CXX=clang-3.8 python ../configure.py --enable-optimize --sdks=episode1,tf2,l4d2,csgo,dota
+  - ambuild