Ninja generator: restore correct encoding for policy CMP0181=OLD

Fixes: #26857

Source/cmGlobalGenerator.cxx

@@ -3891,6 +3891,12 @@ cmGlobalGenerator::StripCommandStyle cmGlobalGenerator::GetStripCommandStyle(
 #endif
 }
 
+std::string cmGlobalGenerator::GetEncodedLiteral(std::string const& lit)
+{
+  std::string result = lit;
+  return this->EncodeLiteral(result);
+}
+
 void cmGlobalGenerator::AddInstallScript(std::string const& file)
 {
   this->InstallScripts.push_back(file);

Source/cmGlobalGenerator.h

@@ -666,6 +666,7 @@ public:
   };
   StripCommandStyle GetStripCommandStyle(std::string const& strip);
 
+  std::string GetEncodedLiteral(std::string const& lit);
   virtual std::string& EncodeLiteral(std::string& lit) { return lit; }
 
   bool CheckCMP0171() const;

Source/cmGlobalNinjaGenerator.cxx

@@ -184,12 +184,6 @@ std::string cmGlobalNinjaGenerator::EncodeRuleName(std::string const& name)
   return encoded;
 }
 
-std::string cmGlobalNinjaGenerator::GetEncodedLiteral(std::string const& lit)
-{
-  std::string result = lit;
-  return this->EncodeLiteral(result);
-}
-
 std::string& cmGlobalNinjaGenerator::EncodeLiteral(std::string& lit)
 {
   cmSystemTools::ReplaceString(lit, "$", "$$");

Source/cmGlobalNinjaGenerator.h

@@ -77,7 +77,6 @@ public:
 
   static std::string EncodeRuleName(std::string const& name);
   std::string& EncodeLiteral(std::string& lit) override;
-  std::string GetEncodedLiteral(std::string const& lit);
   std::string EncodePath(std::string const& path);
 
   std::unique_ptr<cmLinkLineComputer> CreateLinkLineComputer(

Source/cmLocalGenerator.cxx

@@ -2639,7 +2639,8 @@ void cmLocalGenerator::AppendFlags(std::string& flags,
       }
       CM_FALLTHROUGH;
     case cmPolicies::OLD:
-      this->AppendFlags(flags, newFlags);
+      this->AppendFlags(
+        flags, this->GetGlobalGenerator()->GetEncodedLiteral(newFlags));
       break;
     case cmPolicies::NEW:
       if (compileOrLink == cmBuildStep::Link) {