Makefile: add releases target

This target makes zipfile-based releases for the common platforms.

Author: mhagger

.gitignore

@@ -1,2 +1,3 @@
 /.gopath
 /bin
+/releases

Makefile

@@ -26,13 +26,15 @@ bin/git-sizer:
 # Cross-compile for a bunch of common platforms. Note that this
 # doesn't work with USE_ISATTY:
 .PHONY: common-platforms
-common-platforms: \
-	bin/git-sizer-linux-amd64 \
-	bin/git-sizer-linux-386 \
-	bin/git-sizer-darwin-amd64 \
-	bin/git-sizer-darwin-386 \
-	bin/git-sizer-windows-amd64.exe \
-	bin/git-sizer-windows-386.exe
+common-platforms:
+
+# Create releases for a bunch of common platforms. Note that this
+# doesn't work with USE_ISATTY, and VERSION must be set on the command
+# line; e.g.,
+#
+#     make releases VERSION=1.2.3
+.PHONY: releases
+releases:
 
 # Define rules for a bunch of common platforms that are supported by go; see
 #     https://golang.org/doc/install/source#environment
@@ -44,6 +46,20 @@ define PLATFORM_template =
 bin/git-sizer-$(1)-$(2)$(3):
 	mkdir -p bin
 	cd $$(GOPATH)/src/$$(PACKAGE) && GOOS=$(1) GOARCH=$(2) $$(GO) build $$(GOFLAGS) -o $$(ROOTDIR)/$$@ $$(PACKAGE)
+common-platforms: bin/git-sizer-$(1)-$(2)$(3)
+
+# Note that releases don't include code from vendor (they're only used
+# for testing), so no license info is needed from those projects.
+.PHONY: releases/git-sizer-$$(VERSION)-$(1)-$(2).zip
+releases/git-sizer-$$(VERSION)-$(1)-$(2).zip: bin/git-sizer-$(1)-$(2)$(3)
+	if test -z "$$(VERSION)"; then echo "Please set VERSION to make releases"; exit 1; fi
+	mkdir -p releases/tmp-$$(VERSION)-$(1)-$(2)
+	cp README.md LICENSE.md releases/tmp-$$(VERSION)-$(1)-$(2)
+	cp bin/git-sizer-$(1)-$(2)$(3) releases/tmp-$$(VERSION)-$(1)-$(2)/git-sizer$(3)
+	rm -f $$@
+	zip -j $$@ releases/tmp-$$(VERSION)-$(1)-$(2)/*
+	rm -rf releases/tmp-$$(VERSION)-$(1)-$(2)
+releases: releases/git-sizer-$$(VERSION)-$(1)-$(2).zip
 endef
 
 $(eval $(call PLATFORM_template,linux,amd64))