Fix cycleclock.h for gcc/ARM.
Fix cycleclock.h for gcc/ARM.

Currently there are tests for ARMV3 and ARMV6 in cycleclock.h which are not
defined using gcc on ARM. Since there is also a cast to the unknown type
int64 I assume that the ARM code has not been tested. Therefore this patch
replaces the checks for ARMV3 and ARMV6 by checks for __ARM_ARCH. Also, the
cast to int64 is fixed by casting to int64_t.

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