Merge wasi-common into wasmtime

This commit merges [CraneStation/wasi-common] repo as a subdir of
this repo while preserving **all** of git history. There is an
initiative to pull `wasi-common` into [CraneStation/wasmtime], and
[CraneStation/wasmtime] becoming a monorepo. This came about for
several reasons with a common theme of convenience, namely,
having a monorepo:
1. cleans up the problem of dependencies (as we have seen first
   hand with dependabot enabled, it can cause some grief)
2. completely removes the problem of syncing the closely dependent
   repos (e.g., updating `wasi-common` with say a bugfix generally
   implies creating a "sync" commit for pulling in the changes into
   the "parent" repo, in this case, `wasmtime`)
3. mainly for the two reasons above, makes publishing to crates.io
   easier
4. hopefully streamlines the process of getting the community
   involved in contributing to `wasi-common` as now everything
   is one place

[CraneStation/wasi-common]: https://github.com/CraneStation/wasi-common
[CraneStation/wasmtime]: https://github.com/CraneStation/wasmtime

.github/workflows/main.yml

@@ -13,6 +13,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@master
+      with:
+        submodules: true
     - uses: ./.github/actions/install-rust
     - run: cargo fmt --all -- --check
 
@@ -41,6 +43,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@master
+      with:
+        submodules: true
     - uses: ./.github/actions/install-rust
     - run: cargo doc --no-deps -p wasmtime
     - run: cargo doc --no-deps -p wasmtime-api
@@ -52,6 +56,7 @@ jobs:
     - run: cargo doc --no-deps -p wasmtime-runtime
     - run: cargo doc --no-deps -p wasmtime-wasi
     - run: cargo doc --no-deps -p wasmtime-wast
+    - run: cargo doc --no-deps -p wasi-common
     - uses: actions/upload-artifact@v1
       with:
         name: doc-api
@@ -90,10 +95,14 @@ jobs:
       with:
         toolchain: ${{ matrix.rust }}
 
+    # Install wasm32-wasi target in order to build wasi-common's integration
+    # tests
+    - run: rustup target add wasm32-wasi
+
     - run: cargo fetch
 
     # Build and test all features except for lightbeam
-    - run: cargo test --all --exclude lightbeam --exclude wasmtime-wasi-c --exclude wasmtime-py -- --nocapture
+    - run: cargo test --features wasi-common/wasm_tests --all --exclude lightbeam --exclude wasmtime-wasi-c --exclude wasmtime-py -- --nocapture
       env:
         RUST_BACKTRACE: 1
 
@@ -119,6 +128,8 @@ jobs:
         os: [ubuntu-latest, macos-latest, windows-latest]
     steps:
     - uses: actions/checkout@master
+      with:
+        submodules: true
     - uses: ./.github/actions/install-rust
       with:
         toolchain: nightly-2019-08-15
@@ -196,6 +207,10 @@ jobs:
         submodules: true
     - uses: ./.github/actions/install-rust
     - uses: ./.github/actions/binary-compatible-builds
+      
+    # Install wasm32-wasi target in order to build wasi-common's integration
+    # tests
+    - run: rustup target add wasm32-wasi
 
     # Build `wasmtime` and executables
     - run: $CENTOS cargo build --release --bin wasmtime --bin wasm2obj
@@ -204,7 +219,7 @@ jobs:
     - run: $CENTOS cargo build --release --features wasm-c-api --manifest-path wasmtime-api/Cargo.toml
       shell: bash
     # Test what we just built
-    - run: $CENTOS cargo test --release --all --exclude lightbeam --exclude wasmtime-wasi-c --exclude wasmtime-py --exclude wasmtime-api
+    - run: $CENTOS cargo test --features wasi-common/wasm_tests --release --all --exclude lightbeam --exclude wasmtime-wasi-c --exclude wasmtime-py --exclude wasmtime-api
       shell: bash
       env:
         RUST_BACKTRACE: 1