Auto merge of #5009 - lzutao:travis-windows-msvc, r=phansch

Travis: Use windows-msvc target for Windows build

changelog: none
closes #5005

.travis.yml

@@ -26,7 +26,13 @@ env:
 
 before_install:
   - export CARGO_TARGET_DIR="$TRAVIS_BUILD_DIR/target"
-  - curl -sSL https://sh.rustup.rs | sh -s -- -y --default-toolchain=nightly --profile=minimal
+  - |
+    case "$TRAVIS_OS_NAME" in
+      linux ) HOST=x86_64-unknown-linux-gnu;;
+      osx ) HOST=x86_64-apple-darwin;;
+      windows ) HOST=x86_64-pc-windows-msvc;;
+    esac
+  - curl -sSL https://sh.rustup.rs | sh -s -- -y --default-host="$HOST" --default-toolchain=nightly --profile=minimal
   - export PATH="$HOME/.cargo/bin:$PATH"
 install:
   - |