Respect original tool name

Author: stevapple

Sources/TSCBasic/misc.swift

@@ -94,18 +94,12 @@ public func lookupExecutablePath(
 ) -> AbsolutePath? {
 
     // We should have a value to continue.
-#if os(Windows)
-    guard var value = value, !value.isEmpty else {
-        return nil
-    }
-    let isPath = value.contains("\\") || value.contains("/")
-    if !isPath && !value.contains(".") {
-        value.append(executableFileSuffix)
-    }
-#else
     guard let value = value, !value.isEmpty else {
         return nil
     }
+#if os(Windows)
+    let isPath = value.contains(":") || value.contains("\\") || value.contains("/")
+#else
     let isPath = value.contains("/")
 #endif
 
@@ -124,6 +118,11 @@ public func lookupExecutablePath(
     if !isPath {
         // Try to locate in search paths.
         paths.append(contentsOf: searchPaths.map({ $0.appending(component: value) }))
+#if os(Windows)
+        if !value.contains(".") {
+            paths.append(contentsOf: searchPaths.map({ $0.appending(component: value + executableFileSuffix) }))
+        }
+#endif
     }
 
     return paths.first(where: { localFileSystem.isExecutableFile($0) })