Fix WASI.swift to import Musl instead of Glibc on musl-based systems

Author: kateinoigakukun

Sources/WASI/WASI.swift

@@ -4,8 +4,10 @@ import WasmTypes
 
 #if os(macOS) || os(iOS) || os(watchOS) || os(tvOS) || os(visionOS)
     import Darwin
-#elseif os(Linux) || os(FreeBSD) || os(Android)
+#elseif canImport(Glibc)
     import Glibc
+#elseif canImport(Musl)
+    import Musl
 #elseif os(Windows)
     import ucrt
 #else