mingw w64 7.20

mingw-w64x86_64-7.2.0-posix-seh-rt_v5-rev1Mingw-w64isanadvancementoftheoriginalmingw.orgproject,createdtosupporttheGCCcompileronWindowssystems.Ithasforkeditin2007inordertoprovidesupportfor64bitsandnewAPIs.Ithassincethengainedwidespreaduseanddistribution.