Build all platforms in CI

This commit adds a `ci/build.sh` script that checks that libc builds correctly
for some common configurations (`--no-default-features`, `default`,
`extra_traits`) on most targets supported by Rust since Rust 1.13.0 (the oldest
Rust version that libc supports).

The build matrix is refactored into two stages.

The first stage is called `tools-and-build-and-tier1` and it aims to discover
issues quickly by running the documentation and linter builds, as well as
checking that the library builds correctly on all targets in all supported
channels and "problematic" Rust versions; Rust versions adding major new
features like `repr(align)`, `union`, etc. This first stage also runs
libc-test for the tier-1 targets on linux and osx. These builds finish
quickly because no emulation is necessary.

The second stage is called `tier2` and it runs libc-test for all other targets
for which we are currently able to do so.

Closes #1229 .

.travis.yml

@@ -1,112 +1,188 @@
 language: rust
-rust: stable
+rust: nightly
 sudo: required
 dist: xenial
 services: docker
 
+stages:
+  - tools-and-build-and-tier1
+  - tier2
+
 matrix:
   include:
-    # 1.13.0 compat
-    - env: TARGET=x86_64-unknown-linux-gnu
-      rust: 1.13.0
-      script: rm -f Cargo.lock && cargo build
-      install: true
-
-    # build documentation
-    - env: TARGET=x86_64-unknown-linux-gnu
-      rust: nightly
+    # TOOLS
+    - name: "Documentation"
+      env: TARGET=x86_64-unknown-linux-gnu
       script: sh ci/dox.sh
       install: true
-
-    # stable compat
-    - env: TARGET=x86_64-unknown-linux-gnu
+      stage: tools-and-build-and-tier1
+    - name: "Shellcheck"
       install: true
-    - env: TARGET=i686-unknown-linux-gnu
-    - os: osx
-      env: TARGET=x86_64-apple-darwin
+      script:
+        - shellcheck --version
+        - shellcheck ci/*.sh
+      stage: tools-and-build-and-tier1
+    - name: "Style"
+      install: rustup component add rustfmt-preview
+      script:
+        - rustc ci/style.rs && ./style src
+        - cargo fmt --all -- --check
+      stage: tools-and-build-and-tier1
+
+    # BUILD stable, beta, nightly
+    - name: "Build Stable Rust"
+      script: sh ci/build.sh
+      stage: tools-and-build-and-tier1
+      rust: stable
+    - name: "Build Beta Rust"
+      script: sh ci/build.sh
+      stage: tools-and-build-and-tier1
+      rust: beta
+    - name: "Build Nightly Rust"
+      script: sh ci/build.sh
+      stage: tools-and-build-and-tier1
+      rust: nightly
+    - name: "Build Stable Rust"
+      script: sh ci/build.sh
+      stage: tools-and-build-and-tier1
+      rust: stable
+      os: osx
       osx_image: xcode10
-      install: true
-    - os: osx
-      env: TARGET=i686-apple-darwin
+    - name: "Build Beta Rust"
+      script: sh ci/build.sh
+      stage: tools-and-build-and-tier1
+      rust: beta
+      os: osx
       osx_image: xcode10
-    - env: TARGET=arm-linux-androideabi
+    - name: "Build Nightly Rust"
+      script: sh ci/build.sh
+      stage: tools-and-build-and-tier1
+      rust: nightly
+      os: osx
+      osx_image: xcode10
+    - name: "Build Stable Rust 1.13.0"
+      script: sh ci/build.sh
+      stage: tools-and-build-and-tier1
+      rust: 1.13.0
+    - name: "Build Stable Rust 1.19.0"
+      script: sh ci/build.sh
+      stage: tools-and-build-and-tier1
+      rust: 1.19.0
+    - name: "Build Stable Rust 1.24.0"
+      script: sh ci/build.sh
+      stage: tools-and-build-and-tier1
+      rust: 1.24.0
+    - name: "Build Stable Rust 1.25.0"
+      script: sh ci/build.sh
+      stage: tools-and-build-and-tier1
+      rust: 1.25.0
+    - name: "Build Stable Rust 1.30.0"
+      script: sh ci/build.sh
+      stage: tools-and-build-and-tier1
+      rust: 1.30.0
+    - name: "Build Stable Rust 1.13.0"
+      script: sh ci/build.sh
+      stage: tools-and-build-and-tier1
+      rust: 1.13.0
+      os: osx
+      osx_image: xcode10
+    - name: "Build Stable Rust 1.19.0"
+      script: sh ci/build.sh
+      stage: tools-and-build-and-tier1
+      rust: 1.19.0
+      os: osx
+      osx_image: xcode10
+    - name: "Build Stable Rust 1.24.0"
+      script: sh ci/build.sh
+      stage: tools-and-build-and-tier1
+      rust: 1.24.0
+      os: osx
+      osx_image: xcode10
+    - name: "Build Stable Rust 1.25.0"
+      script: sh ci/build.sh
+      stage: tools-and-build-and-tier1
+      rust: 1.25.0
+      os: osx
+      osx_image: xcode10
+    - name: "Build Stable Rust 1.30.0"
+      script: sh ci/build.sh
+      stage: tools-and-build-and-tier1
+      rust: 1.30.0
+      os: osx
+      osx_image: xcode10
+    - env: TARGET=i686-apple-darwin
+      os: osx
+      osx_image: xcode10
+      stage: tools-and-build-and-tier1
+    - env: TARGET=i686-unknown-linux-gnu
+      stage: tools-and-build-and-tier1
+    - env: TARGET=x86_64-apple-darwin
+      os: osx
+      osx_image: xcode10
+      stage: tools-and-build-and-tier1
+    - env: TARGET=x86_64-unknown-linux-gnu
+      stage: tools-and-build-and-tier1
+
+    # Tier 2 targets
     - env: TARGET=aarch64-linux-android
-    # FIXME(#826) should reenable
-    #- env: TARGET=i686-linux-android
-    - env: TARGET=x86_64-linux-android
-    - env: TARGET=x86_64-unknown-linux-musl
-    - env: TARGET=i686-unknown-linux-musl
-    - env: TARGET=arm-unknown-linux-gnueabihf
-    - env: TARGET=arm-unknown-linux-musleabihf
+      stage: tier2
     - env: TARGET=aarch64-unknown-linux-gnu
+      stage: tier2
     - env: TARGET=aarch64-unknown-linux-musl
-    - env: TARGET=powerpc-unknown-linux-gnu
-    - env: TARGET=powerpc64-unknown-linux-gnu
-    - env: TARGET=powerpc64le-unknown-linux-gnu
+      stage: tier2
+    - env: TARGET=arm-linux-androideabi
+      stage: tier2
+    - env: TARGET=arm-unknown-linux-gnueabihf
+      stage: tier2
+    - env: TARGET=arm-unknown-linux-musleabihf
+      stage: tier2
+    - env: TARGET=asmjs-unknown-emscripten
+      stage: tier2
+    - env: TARGET=i686-unknown-linux-musl
+      stage: tier2
+    - env: TARGET=mips-unknown-linux-gnu
+      stage: tier2
     - env: TARGET=mips-unknown-linux-musl
-    - env: TARGET=mipsel-unknown-linux-musl
+      stage: tier2
     - env: TARGET=mips64-unknown-linux-gnuabi64
+      stage: tier2
     - env: TARGET=mips64el-unknown-linux-gnuabi64
-    - env: TARGET=mips-unknown-linux-gnu
+      stage: tier2
+    - env: TARGET=mipsel-unknown-linux-musl
+      stage: tier2
+    - env: TARGET=powerpc-unknown-linux-gnu
+      stage: tier2
+    - env: TARGET=powerpc64-unknown-linux-gnu
+      stage: tier2
+    - env: TARGET=powerpc64le-unknown-linux-gnu
+      stage: tier2
     - env: TARGET=s390x-unknown-linux-gnu
+      stage: tier2
     - env: TARGET=sparc64-unknown-linux-gnu
-    - env: TARGET=asmjs-unknown-emscripten
+      stage: tier2
     - env: TARGET=wasm32-unknown-emscripten
-
-    # beta
-    - env: TARGET=x86_64-unknown-linux-gnu
-      rust: beta
-      install: true
-    - os: osx
-      env: TARGET=x86_64-apple-darwin
-      osx_image: xcode10
-      rust: beta
-      install: true
-
-    # nightly
-    - env: TARGET=x86_64-unknown-linux-gnu
-      rust: nightly
-      install: true
-    - os: osx
-      env: TARGET=x86_64-apple-darwin
-      osx_image: xcode10
-      rust: nightly
-      install: true
-    # not available on stable
-    # without --release the build fails
-    # see https://github.com/rust-lang/rust/issues/45417
+      stage: tier2
+    - env: TARGET=x86_64-linux-android
+      stage: tier2
     - env: TARGET=x86_64-unknown-linux-gnux32 OPT="--release"
-      rust: nightly
-
-    - env: TARGET=wasm32-unknown-unknown
-      install: rustup target add $TARGET
-      script: cargo build --no-default-features --target $TARGET --release
-    - name: "Style"
-      install: rustup component add rustfmt-preview
-      script:
-        - rustc ci/style.rs && ./style src
-        - cargo fmt --all -- --check
-    - name: "Shellcheck"
-      install: true
-      script:
-        - shellcheck --version
-        - shellcheck ci/*.sh
+      stage: tier2
+    - env: TARGET=x86_64-unknown-linux-musl
+      stage: tier2
 
   allow_failures:
       # FIXME: https://github.com/rust-lang/libc/issues/1226
       - env: TARGET=asmjs-unknown-emscripten
       - env: TARGET=wasm32-unknown-emscripten
 
-install: rustup target add $TARGET
+install: rustup target add $TARGET || true
+
 script:
   - cargo generate-lockfile --manifest-path libc-test/Cargo.toml
-  - if [[ $TRAVIS_OS_NAME = "linux" ]]; then
+  - if [[ $TRAVIS_OS_NAME = "linux" ]] && [[ $BUILD_ONLY != "1" ]]; then
       sh ci/run-docker.sh $TARGET;
     else
-      export CARGO_TARGET_DIR=`pwd`/target;
       sh ci/run.sh $TARGET;
     fi
-
 env:
   global:
     secure: "e2/3QjgRN9atOuSHp22TrYG7QVKcYUWY48Hi9b60w+r1+BhPkTseIJLte7WefRhdXtqpjjUJTooKDhnurFOeHaCT+nmBgiv+FPU893sBl4bhesY4m0vgUJVbNZcs6lTImYekWVb+aqjGdgV/XAgCw7c3kPmrZV0MzGDWL64Xaps="