Enable the wasi target on CI

Now that wasi is in nightlies, we can run it on PRs!

.travis.yml

@@ -204,6 +204,9 @@ matrix:
       stage: tier2
     - env: TARGET=x86_64-unknown-linux-musl
       stage: tier2
+    - env: TARGET=wasm32-unknown-wasi
+      rust: nightly
+      stage: tier2
 
   allow_failures:
       # FIXME: android build bots time out irregularly

ci/docker/wasm32-unknown-wasi/Dockerfile

@@ -28,7 +28,7 @@ RUN mv /clang+llvm-8.0.0-x86_64-linux-gnu-ubuntu-18.04 /wasmcc
 # those breaking changes on `libc`'s own CI
 RUN git clone https://github.com/CraneStation/wasi-sysroot && \
   cd wasi-sysroot && \
-  git reset --hard 320054e84f8f2440def3b1c8700cedb8fd697bf8
+  git reset --hard 3ca44511c298cbbc99e690b761310070b3527fe8
 RUN make -C wasi-sysroot install -j $(nproc) WASM_CC=/wasmcc/bin/clang INSTALL_DIR=/wasi-sysroot
 
 # This is a small wrapper script which executes the actual clang binary in
@@ -58,9 +58,9 @@ RUN curl -sSf https://sh.rustup.rs |  sh -s -- -y
 ENV PATH=/root/.cargo/bin:$PATH
 
 RUN apt-get install -y --no-install-recommends python
-RUN git clone https://github.com/CraneStation/wasmtime-wasi wasmtime && \
+RUN git clone https://github.com/CraneStation/wasmtime wasmtime && \
   cd wasmtime && \
-  git reset --hard 4fe2d6084e5b5cc74e69a26860f12750df51d339
+  git reset --hard a1c123c3dd8f9766990efe0f1734a646f61ba8a0
 RUN cargo build --release --manifest-path wasmtime/Cargo.toml
 
 # And finally in the last image we're going to assemble everything together.
@@ -75,9 +75,9 @@ RUN apt-get update && \
     libxml2
 
 # Copy over clang we downloaded to link executables ...
-COPY --from=reference-sysroot /wasmcc /wasmcc/
+COPY --from=wasi-sysroot /wasmcc /wasmcc/
 # ... and the sysroot we built to link executables against ...
-COPY --from=reference-sysroot /wasi-sysroot/ /wasi-sysroot/
+COPY --from=wasi-sysroot /wasi-sysroot/ /wasi-sysroot/
 # ... and finally wasmtime to actually execute binaries
 COPY --from=wasmtime /wasmtime/target/release/wasmtime /usr/bin/
 

src/wasi.rs

@@ -388,12 +388,15 @@ pub const __WASI_WHENCE_CUR: u8 = 0;
 pub const __WASI_WHENCE_END: u8 = 1;
 pub const __WASI_WHENCE_SET: u8 = 2;
 
-#[cfg_attr(feature = "rustc-dep-of-std",
-           link(name = "c", kind = "static",
-                cfg(target_feature = "crt-static")))]
-#[cfg_attr(feature = "rustc-dep-of-std",
-           link(name = "c", cfg(not(target_feature = "crt-static"))))]
-extern {
+#[cfg_attr(
+    feature = "rustc-dep-of-std",
+    link(name = "c", kind = "static", cfg(target_feature = "crt-static"))
+)]
+#[cfg_attr(
+    feature = "rustc-dep-of-std",
+    link(name = "c", cfg(not(target_feature = "crt-static")))
+)]
+extern "C" {
     pub fn _Exit(code: c_int) -> !;
     pub fn _exit(code: c_int) -> !;
     pub fn abort() -> !;
@@ -452,8 +455,8 @@ extern {
     pub fn puts(a: *const c_char) -> c_int;
     pub fn perror(a: *const c_char);
     pub fn srand(a: c_uint);
-    pub fn atexit(a: extern fn()) -> c_int;
-    pub fn at_quick_exit(a: extern fn()) -> c_int;
+    pub fn atexit(a: extern "C" fn()) -> c_int;
+    pub fn at_quick_exit(a: extern "C" fn()) -> c_int;
     pub fn quick_exit(a: c_int) -> !;
     pub fn posix_memalign(a: *mut *mut c_void, b: size_t, c: size_t) -> c_int;
     pub fn rand_r(a: *mut c_uint) -> c_int;
@@ -501,7 +504,7 @@ extern {
 }
 
 #[link(wasm_import_module = "wasi_unstable")]
-extern {
+extern "C" {
     #[link_name = "clock_res_get"]
     pub fn __wasi_clock_res_get(
         clock_id: __wasi_clockid_t,