refactor: merge adjacent same-condition preprocessor blocks

Merge consecutive #ifdef PIP_HAS_FILESYSTEM / PIP_INTROSPECTION / PIP_CAN
blocks that had no code between them into a single guarded block.

libs/main/core/piobject.cpp

@@ -732,10 +732,8 @@ void PIObject::dump(const PIString & line_prefix) const {
 	PICout(PICoutManipulators::AddNewLine) << line_prefix << "    }";
 	PICout(PICoutManipulators::AddNewLine) << line_prefix << "}";
 }
-#endif // PIP_INTROSPECTION
 
 
-#ifdef PIP_INTROSPECTION
 void dumpApplication(bool with_objects) {
 	PIMutexLocker _ml(PIObject::mutexObjects());
 	// printf("dump application ...\n");

libs/main/io_devices/pican.cpp

@@ -32,10 +32,8 @@
 #  ifndef PF_CAN
 #	define PF_CAN AF_CAN
 #  endif
-#endif
 
 
-#ifdef PIP_CAN
 REGISTER_DEVICE(PICAN)
 PRIVATE_DEFINITION_START(PICAN)
 	PIWaitEvent event;

libs/main/io_devices/pidir.h

@@ -218,10 +218,8 @@ private:
 
 	PIString path_, scan_;
 };
-#endif // PIP_HAS_FILESYSTEM
 
 
-#ifdef PIP_HAS_FILESYSTEM
 inline bool operator<(const PIFile::FileInfo & v0, const PIFile::FileInfo & v1) {
 	return (v0.path < v1.path);
 }

libs/main/io_devices/pifile.h

@@ -362,10 +362,8 @@ private:
 	llong _size = -1;
 	PIString prec_str;
 };
-#endif // PIP_HAS_FILESYSTEM
 
 
-#ifdef PIP_HAS_FILESYSTEM
 //! \relatesalso PICout
 //! \~english Output operator to \a PICout.
 //! \~russian Оператор вывода в \a PICout.