Improve sys::Path::makeAbsolute on Win32.

- Patch by Viktor Kutuzov!

 - Minor tweak by me to add llvm_unreachable calls on FIXMEd error paths.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@75424 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Support/SystemUtils.cpp

@@ -51,7 +51,7 @@ sys::Path llvm::FindExecutable(const std::string &ExeName,
 
   // Otherwise check the directory that the calling program is in.  We can do
   // this if ProgramPath contains at least one / character, indicating that it
-  // is a relative path to bugpoint itself.
+  // is a relative path to the executable itself.
   Result = ProgramPath;
   Result.eraseComponent();
   if (!Result.isEmpty()) {