Implement Basic/misc.swift on Windows

Author: gmittert

Sources/Basic/misc.swift

@@ -18,9 +18,20 @@ import Foundation
 ///   - args: The executable arguments.
 public func exec(path: String, args: [String]) throws {
     let cArgs = CStringArray(args)
+  #if os(Windows)
+    guard cArgs.cArray.withUnsafeBufferPointer({
+        $0.withMemoryRebound(to: UnsafePointer<Int8>?.self, {
+          _execv(path, $0.baseAddress) != -1
+        })
+    })
+    else {
+        throw SystemError.exec(errno, path: path, args: args)
+    }
+  #else
     guard execv(path, cArgs.cArray) != -1 else {
         throw SystemError.exec(errno, path: path, args: args)
     }
+  #endif
 }
 
 // MARK: Utility function for searching for executables
@@ -163,13 +174,23 @@ public enum SystemError: Swift.Error {
     case waitpid(Int32)
 }
 
+#if os(Windows)
+import func SPMLibc.strerror_s
+#else
 import func SPMLibc.strerror_r
+#endif
 import var SPMLibc.EINVAL
 import var SPMLibc.ERANGE
 
 extension SystemError: CustomStringConvertible {
     public var description: String {
         func strerror(_ errno: Int32) -> String {
+          #if os(Windows)
+            let cap = 128
+            var buf = [Int8](repeating: 0, count: cap)
+            let _ = SPMLibc.strerror_s(&buf, 128, errno)
+            return "\(String(cString: buf)) (\(errno))"
+          #else
             var cap = 64
             while cap <= 16 * 1024 {
                 var buf = [Int8](repeating: 0, count: cap)
@@ -187,6 +208,7 @@ extension SystemError: CustomStringConvertible {
                 return "\(String(cString: buf)) (\(errno))"
             }
             fatalError("strerror_r error: \(ERANGE)")
+          #endif
         }
 
         switch self {