cmLinkItem: Clarify name of CMP0027 check member

The only purpose of `cmLinkImplItem`'s `FromGenex` member is to decide
whether to check CMP0027.  That won't be needed for link items added by
new interfaces in the future.  Clarify the name to indicate that we do
not always need to know if the item came from a generator expression.

Source/cmGeneratorTarget.cxx

@@ -3645,7 +3645,7 @@ void processIncludeDirectories(cmGeneratorTarget const* tgt,
     cmLinkImplItem const& item = entry.LinkImplItem;
     std::string const& targetName = item.AsStr();
     bool const fromImported = item.Target && item.Target->IsImported();
-    bool const checkCMP0027 = item.FromGenex;
+    bool const checkCMP0027 = item.CheckCMP0027;
 
     std::string usedIncludes;
     for (std::string& entryInclude : entry.Values) {
@@ -7935,7 +7935,7 @@ void cmGeneratorTarget::ComputeLinkImplementationLibraries(
     std::string const& evaluated =
       cge->Evaluate(this->LocalGenerator, config, head, &dagChecker, nullptr,
                     this->LinkerLanguage);
-    bool const fromGenex = evaluated != entry.Value;
+    bool const checkCMP0027 = evaluated != entry.Value;
     cmExpandList(evaluated, llibs);
     if (cge->GetHadHeadSensitiveCondition()) {
       impl.HadHeadSensitiveCondition = true;
@@ -8009,7 +8009,7 @@ void cmGeneratorTarget::ComputeLinkImplementationLibraries(
         }
       }
 
-      impl.Libraries.emplace_back(std::move(item), fromGenex);
+      impl.Libraries.emplace_back(std::move(item), checkCMP0027);
     }
 
     std::set<std::string> const& seenProps = cge->GetSeenTargetProperties();

Source/cmLinkItem.cxx

@@ -68,8 +68,8 @@ cmLinkImplItem::cmLinkImplItem()
 {
 }
 
-cmLinkImplItem::cmLinkImplItem(cmLinkItem item, bool fromGenex)
+cmLinkImplItem::cmLinkImplItem(cmLinkItem item, bool checkCMP0027)
   : cmLinkItem(std::move(item))
-  , FromGenex(fromGenex)
+  , CheckCMP0027(checkCMP0027)
 {
 }

Source/cmLinkItem.h

@@ -40,8 +40,8 @@ class cmLinkImplItem : public cmLinkItem
 {
 public:
   cmLinkImplItem();
-  cmLinkImplItem(cmLinkItem item, bool fromGenex);
-  bool FromGenex = false;
+  cmLinkImplItem(cmLinkItem item, bool checkCMP0027);
+  bool CheckCMP0027 = false;
 };
 
 /** The link implementation specifies the direct library