Add support of custom rules

Fixes: #27383

Source/cmCustomRule.cxx

@@ -0,0 +1,55 @@
+/* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+   file LICENSE.rst or https://cmake.org/licensing for details.  */
+#include <string>
+#include <utility>
+#include <vector>
+
+#include "cmRule.h"
+
+class cmMakefile;
+
+cmCustomRule::cmCustomRule(cmMakefile& makefile, std::string name,
+                           CustomCommands commands,
+                           std::vector<std::string> outputs,
+                           cm::RuleScope scope)
+  : cmRule(makefile, name, scope)
+  , Commands(std::move(commands))
+  , Outputs(std::move(outputs))
+{
+}
+
+cmCustomRule::CustomCommands const& cmCustomRule::GetCommands() const
+{
+  return this->Commands;
+}
+std::vector<std::string> const& cmCustomRule::GetOutputs() const
+{
+  return this->Outputs;
+}
+
+void cmCustomRule::SetByproducts(std::vector<std::string> byproducts)
+{
+  this->Byproducts = std::move(byproducts);
+}
+std::vector<std::string> const& cmCustomRule::GetByproducts() const
+{
+  return this->Byproducts;
+}
+
+void cmCustomRule::SetDepends(std::vector<std::string> depends)
+{
+  this->Depends = std::move(depends);
+}
+std::vector<std::string> const& cmCustomRule::GetDepends() const
+{
+  return this->Depends;
+}
+
+void cmCustomRule::SetDepfile(std::string depfile)
+{
+  this->Depfile = std::move(depfile);
+}
+std::string const& cmCustomRule::GetDepfile() const
+{
+  return this->Depfile;
+}