Correct OptionCategoryCompare() in the command line library.

[dsanders]

Summary

It should return <0, 0, or >0 for less-than, equal, and greater-than like
strcmp() (according to the history, it used to be implemented with
strcmp()) but it actually returned 0, or 1 for not-equal and equal.

[qcolombet]

LGTM

lib/Support/CommandLine.cpp

 };
 
 class CategorizedHelpPrinter : public HelpPrinter {
 public:
   explicit CategorizedHelpPrinter(bool showHidden) : HelpPrinter(showHidden) {}
 
   // Helper function for printOptions().
   // It shall return a negative value if A's name should be lexicographically
-  // ordered before B's name. It returns a value greater equal zero otherwise.
+  // ordered before B's name. It returns a value greater than zero if B's name
+  // should be ordered before A's name, and it returns 0 otherwise.
   static int OptionCategoryCompare(OptionCategory *const *A,
                                    OptionCategory *const *B) {
-    return (*A)->getName() == (*B)->getName();
+    return (*A)->getName().compare((*B)->getName());
   }
 
   // Make sure we inherit our base class's operator=()
   using HelpPrinter::operator=;
 
 protected:
   void printOptions(StrOptionPairVector &Opts, size_t MaxArgLen) override {
     std::vector<OptionCategory *> SortedCategories;