config is lazy_static to amoritze it

crates/test-programs/wasi-tests/src/config.rs

@@ -0,0 +1,48 @@
+pub struct TestConfig {
+    errno_mode: ErrnoMode,
+    no_dangling_symlinks: bool,
+    no_fd_allocate: bool,
+}
+
+enum ErrnoMode {
+    Linux,
+    Windows,
+    Permissive,
+}
+
+impl TestConfig {
+    pub fn from_env() -> Self {
+        let errno_mode = if std::env::var("ERRNO_MODE_LINUX").is_ok() {
+            ErrnoMode::Linux
+        } else if std::env::var("ERRNO_MODE_WINDOWS").is_ok() {
+            ErrnoMode::Windows
+        } else {
+            ErrnoMode::Permissive
+        };
+        let no_dangling_symlinks = std::env::var("NO_DANGLING_SYMLINKS").is_ok();
+        let no_fd_allocate = std::env::var("NO_FD_ALLOCATE").is_ok();
+        TestConfig {
+            errno_mode,
+            no_dangling_symlinks,
+            no_fd_allocate,
+        }
+    }
+    pub fn errno_expect_linux(&self) -> bool {
+        match self.errno_mode {
+            ErrnoMode::Linux => true,
+            _ => false,
+        }
+    }
+    pub fn errno_expect_windows(&self) -> bool {
+        match self.errno_mode {
+            ErrnoMode::Windows => true,
+            _ => false,
+        }
+    }
+    pub fn support_dangling_symlinks(&self) -> bool {
+        !self.no_dangling_symlinks
+    }
+    pub fn support_fd_allocate(&self) -> bool {
+        !self.no_fd_allocate
+    }
+}