Use ADD_ASSIMP_IMPORTER for STEP importer

code/ImporterRegistry.cpp

@@ -197,7 +197,7 @@ corresponding preprocessor flag to selectively disable formats.
 #ifndef ASSIMP_BUILD_NO_MMD_IMPORTER
 #   include "MMDImporter.h"
 #endif
-#ifndef ASSIMP_BUILD_NO_STEPFILE_IMPORTER
+#ifndef ASSIMP_BUILD_NO_STEP_IMPORTER
 #   include "Importer/StepFile/StepFileImporter.h"
 #endif
 
@@ -355,7 +355,7 @@ void GetImporterInstanceList(std::vector< BaseImporter* >& out)
 #ifndef ASSIMP_BUILD_NO_MMD_IMPORTER
     out.push_back( new MMDImporter() );
 #endif
-#ifndef ASSIMP_BUILD_NO_STEPFILE_IMPORTER
+#ifndef ASSIMP_BUILD_NO_STEP_IMPORTER
     out.push_back(new StepFile::StepFileImporter());
 #endif
 }