Use strtoll when reading mtime from build log.
Use strtoll when reading mtime from build log.

This prevents overflow on Windows where 'long' is not 64-bit.

ndsol/subninja,atetubou/ninja,atetubou/ninja,martine/ninja,sgraham/ninja,nico/ninja,iwadon/ninja,iwadon/ninja,nico/ninja,nico/ninja,atetubou/ninja,ninja-build/ninja,nico/ninja,maruel/ninja,fuchsia-mirror/third_party-ninja,maruel/ninja,AoD314/ninja,ndsol/subninja,nicolasdespres/ninja,ndsol/subninja,bradking/ninja,martine/ninja,Qix-/ninja,martine/ninja,martine/ninja,AoD314/ninja,sgraham/ninja,ndsol/subninja,ninja-build/ninja,bradking/ninja,mydongistiny/ninja,nicolasdespres/ninja,Qix-/ninja,mydongistiny/ninja,nicolasdespres/ninja,AoD314/ninja,bradking/ninja,lizh06/ninja,sgraham/ninja,Qix-/ninja,iwadon/ninja,fuchsia-mirror/third_party-ninja,ninja-build/ninja,Qix-/ninja,maruel/ninja,ninja-build/ninja,mydongistiny/ninja,lizh06/ninja,AoD314/ninja,mydongistiny/ninja,atetubou/ninja,nicolasdespres/ninja,iwadon/ninja,sgraham/ninja,maruel/ninja,lizh06/ninja,fuchsia-mirror/third_party-ninja,fuchsia-mirror/third_party-ninja,lizh06/ninja,bradking/ninja