Use `int64_t` rather than `int64`
Use `int64_t` rather than `int64`

For cross platform and cross compiler portability we use the
standard integer type for a 64-bit integer. MinGW on Windows doesn't
have the definition for `int64`.

disconnect3d/benchmark,xlqian/benchmark,nickhutchinson/benchmark,google/benchmark,google/benchmark,bowlofstew/benchmark,nickhutchinson/benchmark-cxx03,everbase/benchmark,LepelTsmok/benchmark,efcs/benchmark,everbase/benchmark,disconnect3d/benchmark,efcs/benchmark,nickhutchinson/benchmark,codygray/benchmark,ntx-/benchmark,ntx-/benchmark,Photonomie/benchmark,gezidan/benchmark,LepelTsmok/benchmark,ntx-/benchmark,subailong/benchmark,chemhack/benchmark,fuchsia-mirror/third_party-benchmark,quantumsteve/benchmark,ntx-/benchmark,chandlerc/benchmark,bowlofstew/benchmark,fuchsia-mirror/third_party-benchmark,mockingbirdnest/benchmark,mockingbirdnest/benchmark,subailong/benchmark,bowlofstew/benchmark,fuchsia-mirror/third_party-benchmark,codygray/benchmark,efcs/benchmark,disconnect3d/benchmark,nickhutchinson/benchmark,gezidan/benchmark,everbase/benchmark,nickhutchinson/benchmark-cxx03,quantumsteve/benchmark,xlqian/benchmark,mockingbirdnest/benchmark,eliben/benchmark,quantumsteve/benchmark,nickhutchinson/benchmark,LepelTsmok/benchmark,mockingbirdnest/benchmark,chandlerc/benchmark,nickhutchinson/benchmark-cxx03,fuchsia-mirror/third_party-benchmark,eliben/benchmark,bowlofstew/benchmark,Photonomie/benchmark,chemhack/benchmark,eliben/benchmark,chandlerc/benchmark,LepelTsmok/benchmark,everbase/benchmark,nickhutchinson/benchmark-cxx03,codygray/benchmark,Photonomie/benchmark,eliben/benchmark,quantumsteve/benchmark,subailong/benchmark,efcs/benchmark,xlqian/benchmark,gezidan/benchmark,chemhack/benchmark,chemhack/benchmark,xlqian/benchmark,chandlerc/benchmark,subailong/benchmark,Photonomie/benchmark,disconnect3d/benchmark,google/benchmark,codygray/benchmark,gezidan/benchmark