get circle to save dev builds for windows, linux, and darwin

.circleci/config.yml

@@ -46,17 +46,33 @@ jobs:
     <<: *golang
     environment:
       GOOS: openbsd
-  generate_binaries:
+  save_windows_binary:
     <<: *golang
     steps:
       - checkout
-      - run: PATH=$PATH:$GOPATH/bin XC_ARCH=amd64 XC_OS="linux windows darwin" GOLDFLAGS="-s -w" ./scripts/build.sh
-      - run: mkdir ./pkg/zipped_packers
-      - run: zip ./pkg/zipped_packers/packer_darwin.zip ./pkg/darwin_amd64/packer
-      - run: zip ./pkg/zipped_packers/packer_windows.zip ./pkg/windows_amd64/packer
-      - run: zip ./pkg/zipped_packers/packer_linux.zip ./pkg/linux_amd64/packer
+      - run: go get github.com/mitchellh/gox
+      - run: PATH=$PATH:$GOPATH/bin XC_ARCH=amd64 XC_OS="windows" GOLDFLAGS="-s -w" ./scripts/build.sh
+      - run: zip ./pkg/packer_windows.zip ./pkg/windows_amd64/packer.exe
       - store_artifacts:
-          path: ./pkg/zipped_packers
+          path: ./pkg/packer_windows.zip
+  save_linux_binary:
+    <<: *golang
+    steps:
+      - checkout
+      - run: go get github.com/mitchellh/gox
+      - run: PATH=$PATH:$GOPATH/bin XC_ARCH=amd64 XC_OS="linux" GOLDFLAGS="-s -w" ./scripts/build.sh
+      - run: zip ./pkg/packer_linux.zip ./pkg/linux_amd64/packer
+      - store_artifacts:
+          path: ./pkg/packer_linux.zip
+  save_darwin_binary:
+    <<: *golang
+    steps:
+      - checkout
+      - run: go get github.com/mitchellh/gox
+      - run: PATH=$PATH:$GOPATH/bin XC_ARCH=amd64 XC_OS="darwin" GOLDFLAGS="-s -w" ./scripts/build.sh
+      - run: zip ./pkg/packer_darwin.zip ./pkg/darwin_amd64/packer
+      - store_artifacts:
+          path: ./pkg/packer_darwin.zip
 
 workflows:
   version: 2
@@ -70,4 +86,6 @@ workflows:
       - build_freebsd
       - build_openbsd
       - build_solaris
-      - generate_binaries
+      - save_darwin_binary
+      - save_linux_binary
+      - save_windows_binary