Update from xgo to gox; add basic test for binaries

Makefile

@@ -39,10 +39,11 @@ lint:
 	@golint ./cmd/jira
 
 all:
-	GO111MODULE=off $(GO) get -u src.techknowlogick.com/xgo
+	GO111MODULE=off $(GO) get -u github.com/mitchellh/gox
 	rm -rf dist
 	mkdir -p dist
-	xgo --targets="freebsd/amd64,linux/386,linux/amd64,windows/386,windows/amd64,darwin/amd64" -dest ./dist -ldflags="-w -s" ./cmd/jira
+	gox -ldflags="-w -s" -output="dist/github.com/go-jira/jira-{{.OS}}-{{.Arch}}" -osarch="darwin/amd64 linux/386 linux/amd64 windows/386 windows/amd64" ./...
+	_t/test_binaries.sh
 
 install:
 	${MAKE} GOBIN=$$HOME/bin build

_t/test_binaries.sh

@@ -0,0 +1,40 @@
+#!/bin/bash
+
+#dist/github.com/go-jira/jira-darwin-amd64      dist/github.com/go-jira/jira-linux-amd64       dist/github.com/go-jira/jira-windows-amd64.exe
+#dist/github.com/go-jira/jira-linux-386         dist/github.com/go-jira/jira-windows-386.exe
+
+EXIT_CODE=0
+
+function error() {
+  echo $1
+  EXIT_CODE=1
+}
+
+DIST_DIR="dist/github.com/go-jira"
+
+out=`file ${DIST_DIR}/jira-darwin-amd64 2>&1`
+if ! [[ "$out" =~ "Mach-O 64-bit executable x86_64" ]]; then
+   error "darwin/amd64 build not as expected: $out"
+fi
+
+out=`file ${DIST_DIR}/jira-linux-amd64 2>&1`
+if ! [[ "$out" =~ "ELF 64-bit LSB executable, x86-64" ]]; then
+   error "linux/amd64 build not as expected: $out"
+fi
+
+out=`file ${DIST_DIR}/jira-linux-386 2>&1`
+if ! [[ "$out" =~ "ELF 32-bit LSB executable, Intel 80386" ]]; then
+   error "linux/i386 build not as expected: $out"
+fi
+
+out=`file ${DIST_DIR}/jira-windows-amd64.exe 2>&1`
+if ! [[ "$out" =~ "PE32+ executable (console) x86-64" ]]; then
+   error "windows/amd64 build not as expected: $out"
+fi
+
+out=`file ${DIST_DIR}/jira-windows-386.exe 2>&1`
+if ! [[ "$out" =~ "PE32 executable (console) Intel 80386" ]]; then
+   error "windows/i386 build not as expected: $out"
+fi
+
+exit $EXIT_CODE