use sudo to get a travis worker with avx2 support

.travis.yml

@@ -10,21 +10,27 @@ rust:
 env:
     -
     - CARGO_CFG_HTTPARSE_DISABLE_SIMD=1
-    - CARGO_CFG_HTTPARSE_DISABLE_SIMD_COMPILETIME=1 RUSTFLAGS="-C target_feature=+avx2"
     - CARGO_CFG_HTTPARSE_DISABLE_SIMD_COMPILETIME=1 RUSTFLAGS="-C target_feature=+sse4.2"
-    - CARGO_CFG_HTTPARSE_DISABLE_SIMD_COMPILETIME=1 RUSTFLAGS="-C target_feature=+sse4.2,+avx2"
+    #- CARGO_CFG_HTTPARSE_DISABLE_SIMD_COMPILETIME=1 RUSTFLAGS="-C target_feature=+avx2"
+    #- CARGO_CFG_HTTPARSE_DISABLE_SIMD_COMPILETIME=1 RUSTFLAGS="-C target_feature=+sse4.2,+avx2"
     - RUSTFLAGS="-C target_feature=+sse4.2"
-    - RUSTFLAGS="-C target_feature=+avx2"
-    - RUSTFLAGS="-C target_feature=+sse4.2,+avx2"
+    #- RUSTFLAGS="-C target_feature=+avx2"
+    #- RUSTFLAGS="-C target_feature=+sse4.2,+avx2"
 
 matrix:
-    fast_finish: true
+    #fast_finish: true
     include:
         - rust: 1.10.0 # minimum Rust version
+          script: # don't run tests, since dev-dependencies don't build on 1.10
+              - cargo build --no-default-features
+              - cargo build
+        - rust: nightly
+          sudo: true # supposedly with sudo, the worker has avx2 support?
+          env: RUSTFLAGS="-C target_feature=+avx2"
 
 script:
     - cargo build --no-default-features
-    - 'if [ "$TRAVIS_RUST_VERSION" != "1.10.0" ]; then cargo test --no-default-features; fi'
+    - cargo test --no-default-features
     - cargo build
-    - 'if [ "$TRAVIS_RUST_VERSION" != "1.10.0" ]; then cargo test; fi'
+    - cargo test