fix bash calls

appveyor.yml

@@ -34,18 +34,19 @@ cache:
 
 clone_folder: c:\gopath\src\github.com\hashicorp\packer
 
+# Install needed build dependencies
 install:
   - ps: if (Test-Path Env:\CYG_ROOT) { Start-FileDownload "https://cygwin.com/$env:CYG_SETUP" -FileName "$env:CYG_SETUP" }
-  - %CYG_SETUP% --quiet-mode --no-shortcuts --only-site --root "%CYG_ROOT%" --site "%CYG_MIRROR%" --local-package-dir "%CYG_CACHE%" --packages "%CYG_PACKAGES%" --upgrade-also
+  - if defined CYG_ROOT (%CYG_SETUP% --quiet-mode --no-shortcuts --only-site --root "%CYG_ROOT%" --site "%CYG_MIRROR%" --local-package-dir "%CYG_CACHE%" --packages "%CYG_PACKAGES%" --upgrade-also)
   - echo %Path%
   - go version
   - go env
 
 build_script:
   - git rev-parse HEAD
-  - make deps
+  - (%BASH% -lc "make deps")
 
 test_script:
-  - make ci
+  - (%BASH% -lc "make ci")
 
 deploy: off