Make FindProgramByName return paths with slashes unmodified on Windows.

This makes its behaviour more consistent across platforms.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118048 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/System/Win32/Program.inc b/lib/System/Win32/Program.inc
index b55aa2f..2d6e665 100644
--- a/lib/System/Win32/Program.inc
+++ b/lib/System/Win32/Program.inc
@@ -67,10 +67,12 @@
   Path temp;
   if (!temp.set(progName)) // invalid name
     return Path();
-  if (temp.canExecute()) // already executable as is
+  // Return paths with slashes verbatim.
+  if (progName.find('\\') != std::string::npos ||
+      progName.find('/') != std::string::npos)
     return temp;
 
-  // At this point, the file name is valid and its not executable.
+  // At this point, the file name is valid and does not contain slashes.
   // Let Windows search for it.
   char buffer[MAX_PATH];
   char *dummy = NULL;