Travis: Try a workaround for the llvm repository being down

.travis.yml

@@ -12,20 +12,32 @@ os:
   - linux
   # - osx
 
-sudo: false
+env:
+  global:
+    - LLVM_VERSION=3.8.0
+    - LLVM_ARCHIVE_PATH=$HOME/clang+llvm.tar.xz
+
+dist: trusty
+sudo: required
 addons:
   apt:
     sources:
       - ubuntu-toolchain-r-test
-      - llvm-toolchain-precise
+      # - llvm-toolchain-precise
     packages:
-      - clang-3.8
+      # - clang-3.8
-      - clang-format-3.8
+      # - clang-format-3.8
 
 git:
   # We handle submodules ourselves in xenia-build setup.
   submodules: false
 
+before_install:
+  - wget http://llvm.org/releases/$LLVM_VERSION/clang+llvm-$LLVM_VERSION-x86_64-linux-gnu-ubuntu-14.04.tar.xz -O $LLVM_ARCHIVE_PATH
+  - mkdir $HOME/clang+llvm
+  - tar xf $LLVM_ARCHIVE_PATH -C $HOME/clang+llvm --strip-components 1
+  - export PATH=$HOME/clang+llvm/bin:$PATH
+
 before_script:
   # Dump useful info.
   - $CXX --version