PCH: add target_precompile_headers command

Source/cmTargetPrecompileHeadersCommand.h

@@ -0,0 +1,41 @@
+/* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+   file Copyright.txt or https://cmake.org/licensing for details.  */
+#ifndef cmTargetPrecompileHeadersCommand_h
+#define cmTargetPrecompileHeadersCommand_h
+
+#include "cmConfigure.h" // IWYU pragma: keep
+
+#include <string>
+#include <vector>
+
+#include "cm_memory.hxx"
+
+#include "cmCommand.h"
+
+#include "cmTargetPropCommandBase.h"
+
+class cmExecutionStatus;
+class cmTarget;
+
+class cmTargetPrecompileHeadersCommand : public cmTargetPropCommandBase
+{
+public:
+  std::unique_ptr<cmCommand> Clone() override
+  {
+    return cm::make_unique<cmTargetPrecompileHeadersCommand>();
+  }
+
+  bool InitialPass(std::vector<std::string> const& args,
+                   cmExecutionStatus& status) override;
+
+private:
+  void HandleMissingTarget(const std::string& name) override;
+
+  bool HandleDirectContent(cmTarget* tgt,
+                           const std::vector<std::string>& content,
+                           bool prepend, bool system) override;
+
+  std::string Join(const std::vector<std::string>& content) override;
+};
+
+#endif