Make the Windows build not depend on the source being a git repository.
Make the Windows build not depend on the source being a git repository.

Fixes #2095.

boemmels/ponyc,kulibali/ponyc,Perelandric/ponyc,Perelandric/ponyc,jemc/ponyc,dipinhora/ponyc,Perelandric/ponyc,Perelandric/ponyc,Praetonus/ponyc,ponylang/ponyc,cquinn/ponyc,CausalityLtd/ponyc,sgebbie/ponyc,cquinn/ponyc,Theodus/ponyc,jemc/ponyc,Theodus/ponyc,sgebbie/ponyc,boemmels/ponyc,cquinn/ponyc,Praetonus/ponyc,Theodus/ponyc,ponylang/ponyc,sgebbie/ponyc,kulibali/ponyc,sgebbie/ponyc,sgebbie/ponyc,Praetonus/ponyc,kulibali/ponyc,cquinn/ponyc,Perelandric/ponyc,boemmels/ponyc,boemmels/ponyc,Praetonus/ponyc,ponylang/ponyc,CausalityLtd/ponyc,boemmels/ponyc,dipinhora/ponyc,dipinhora/ponyc,jemc/ponyc,kulibali/ponyc,Theodus/ponyc,Theodus/ponyc,CausalityLtd/ponyc