fix for #6279#6253
mk: rt.mk regression patch for mingw32 after #6176
currently do not pass optimization option just make it works only
mk: target.mk host.mk fix for duplicated rules of mingw32 after #6235
It can be simply fixed with CFG_LIB check whether bin or lib however considering multiple target triples with linux and windows, CFG_LIB needs to configurable #5223 and #5577