code/CMakeFiles/assimp.dir/Importer/StepFile/StepFileGen1.cpp.o' failed
Add this in CmkaeList.txt
set(CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS} "-O3")
And then add this in your cmake command
cmake -DASSIMP_BUILD_ASSIMP_TOOLS=OFF -DASSIMP_BUILD_TESTS=OFF