find_package: Don't glob certain macOS paths

Modify cmDirectoryListGenerator to support exact matching as well as
'starts-with' matching. The latter is used to implement '<name>*' search
paths, but cmDirectoryListGenerator is also used for '<name><suffix>'
matching (via cmMacProjectDirectoryListGenerator, mainly for macOS
paths), which resulted in the latter actually matching '<name><suffix>*'
even though that is not documented and unlikely to be useful.

This also adds the ability for cmDirectoryListGenerator to match
anything (by giving an empty list of names), which isn't in use yet, but
which we will use in the future.

Source/cmFindPackageCommand.cxx

@@ -206,8 +206,10 @@ private:
 class cmDirectoryListGenerator
 {
 public:
-  cmDirectoryListGenerator(std::vector<std::string> const& names)
+  cmDirectoryListGenerator(std::vector<std::string> const& names,
+                           bool exactMatch)
     : Names{ names }
+    , ExactMatch{ exactMatch }
     , Current{ this->Matches.cbegin() }
   {
   }
@@ -231,20 +233,28 @@ public:
       // `isDirentryToIgnore(i)` condition to check.
       for (auto i = 0ul; i < directoryLister.GetNumberOfFiles(); ++i) {
         const char* const fname = directoryLister.GetFile(i);
-        if (isDirentryToIgnore(fname)) {
+        // Skip entries to ignore or that aren't directories.
+        if (isDirentryToIgnore(fname) || !directoryLister.FileIsDirectory(i)) {
           continue;
         }
 
-        for (const auto& n : this->Names.get()) {
-          // NOTE Customization point for `cmMacProjectDirectoryListGenerator`
-          const auto name = this->TransformNameBeforeCmp(n);
-          // Skip entries that don't match and non-directories.
-          // ATTENTION BTW, original code also didn't check if it's a symlink
-          // to a directory!
-          const auto equal =
-            (cmsysString_strncasecmp(fname, name.c_str(), name.length()) == 0);
-          if (equal && directoryLister.FileIsDirectory(i)) {
-            this->Matches.emplace_back(fname);
+        if (!this->ExactMatch && this->Names.get().empty()) {
+          this->Matches.emplace_back(fname);
+        } else {
+          for (const auto& n : this->Names.get()) {
+            // NOTE Customization point for
+            // `cmMacProjectDirectoryListGenerator`
+            const auto name = this->TransformNameBeforeCmp(n);
+            // Skip entries that don't match.
+            const auto equal =
+              ((this->ExactMatch
+                  ? cmsysString_strcasecmp(fname, name.c_str())
+                  : cmsysString_strncasecmp(fname, name.c_str(),
+                                            name.length())) == 0);
+            if (equal) {
+              this->Matches.emplace_back(fname);
+              break;
+            }
           }
         }
       }
@@ -273,6 +283,7 @@ protected:
   virtual std::string TransformNameBeforeCmp(std::string same) { return same; }
 
   std::reference_wrapper<const std::vector<std::string>> Names;
+  bool const ExactMatch;
   std::vector<std::string> Matches;
   std::vector<std::string>::const_iterator Current;
 };
@@ -282,8 +293,9 @@ class cmProjectDirectoryListGenerator : public cmDirectoryListGenerator
 public:
   cmProjectDirectoryListGenerator(std::vector<std::string> const& names,
                                   cmFindPackageCommand::SortOrderType so,
-                                  cmFindPackageCommand::SortDirectionType sd)
-    : cmDirectoryListGenerator{ names }
+                                  cmFindPackageCommand::SortDirectionType sd,
+                                  bool exactMatch)
+    : cmDirectoryListGenerator{ names, exactMatch }
     , SortOrder{ so }
     , SortDirection{ sd }
   {
@@ -310,7 +322,7 @@ class cmMacProjectDirectoryListGenerator : public cmDirectoryListGenerator
 public:
   cmMacProjectDirectoryListGenerator(const std::vector<std::string>& names,
                                      cm::string_view ext)
-    : cmDirectoryListGenerator{ names }
+    : cmDirectoryListGenerator{ names, true }
     , Extension{ ext }
   {
   }
@@ -2666,7 +2678,7 @@ bool cmFindPackageCommand::SearchPrefix(std::string const& prefix_in)
   auto iCMakeGen = cmCaseInsensitiveDirectoryListGenerator{ "cmake"_s };
   auto firstPkgDirGen =
     cmProjectDirectoryListGenerator{ this->Names, this->SortOrder,
-                                     this->SortDirection };
+                                     this->SortDirection, false };
 
   // PREFIX/(cmake|CMake)/ (useful on windows or in build trees)
   if (TryGeneratedPaths(searchFn, prefix, iCMakeGen)) {
@@ -2685,7 +2697,7 @@ bool cmFindPackageCommand::SearchPrefix(std::string const& prefix_in)
 
   auto secondPkgDirGen =
     cmProjectDirectoryListGenerator{ this->Names, this->SortOrder,
-                                     this->SortDirection };
+                                     this->SortDirection, false };
 
   // PREFIX/(Foo|foo|FOO).*/(cmake|CMake)/(Foo|foo|FOO).*/
   if (TryGeneratedPaths(searchFn, prefix, firstPkgDirGen, iCMakeGen,