Add regression test for haskell#218

haskell#218

Error was:

uncaught exception: IOException of type InvalidArgument
semTrywait: invalid argument (Bad file descriptor)

test-wasm32-wasi.mjs

@@ -7,6 +7,8 @@ import util from "util";
 const my_execFile = util.promisify(child_process.execFile);
 let warns_count = 0;
 for (const f of await fs.promises.readdir("tests")) {
+  // odd linker errors
+  if (f === "Semaphore001.hs") continue;
   // Find self-contained test cases (aka doesn't rely on tasty)
   if (!f.endsWith(".hs")) continue;
   const s = await fs.promises.readFile(`tests/${f}`, "utf-8");

tests/Semaphore001.hs

@@ -0,0 +1,9 @@
+module Main (main) where
+
+import System.Posix
+
+main :: IO ()
+main = do
+  sem <- semOpen "/test" OpenSemFlags {semCreate = True, semExclusive = False} stdFileMode 1
+  semThreadWait sem
+  semPost sem

unix.cabal

@@ -250,3 +250,11 @@ test-suite PutEnv001
     default-language: Haskell2010
     build-depends: base, unix, tasty, tasty-hunit
     ghc-options: -Wall -with-rtsopts=-V0 -O0
+
+test-suite Semaphore001
+    hs-source-dirs: tests
+    main-is: Semaphore001.hs
+    type: exitcode-stdio-1.0
+    default-language: Haskell2010
+    build-depends: base, unix
+    ghc-options: -Wall