[Travis] Update Travis to use Xenial and more recent compilers

.travis.yml

@@ -9,16 +9,16 @@ os:
   # - osx
 
 sudo: required
-dist: trusty
+dist: xenial
 addons:
   apt:
     sources:
       - ubuntu-toolchain-r-test
-      - llvm-toolchain-trusty-4.0
+      - llvm-toolchain-xenial-6.0
     packages:
-      - clang-4.0
-      - llvm-4.0-dev
-      - g++-5
+      - clang-6.0
+      - llvm-6.0-dev
+      - g++-8
       - python3
       - libc++-dev
       - libc++abi-dev
@@ -32,10 +32,10 @@ addons:
 
 matrix:
   include:
-    - env: C_COMPILER=clang-4.0 CXX_COMPILER=clang++-4.0 LINT=true
+    - env: C_COMPILER=clang-6.0 CXX_COMPILER=clang++-6.0 LINT=true
       sudo: false
-    - env: C_COMPILER=clang-4.0 CXX_COMPILER=clang++-4.0 BUILD=true CONFIG=Debug
-    - env: C_COMPILER=clang-4.0 CXX_COMPILER=clang++-4.0 BUILD=true CONFIG=Release
+    - env: C_COMPILER=clang-6.0 CXX_COMPILER=clang++-6.0 BUILD=true CONFIG=Debug
+    - env: C_COMPILER=clang-6.0 CXX_COMPILER=clang++-6.0 BUILD=true CONFIG=Release
 
 git:
   # We handle submodules ourselves in xenia-build setup.
@@ -72,3 +72,4 @@ script:
   #- ./xenia-build test --config=debug --no-build -- --enable_haswell_instructions=false
   # All tests (with haswell support).
   #- ./xenia-build test --config=debug --no-build -- --enable_haswell_instructions=true
+