build: Add release builds, now generated with 'make release'

Currently supported platforms are

    - linux{amd64,arm,386}
    - winows{amd64,386}
    - darwin{amd64}

buildscripts/build.sh

@@ -0,0 +1,48 @@
+#!/bin/bash
+
+_init() {
+    # Save release LDFLAGS
+    LDFLAGS=$(go run buildscripts/gen-ldflags.go)
+
+    # Extract release tag
+    release_tag=$(echo $LDFLAGS | awk {'print $4'} | cut -f2 -d=)
+
+    # Verify release tag.
+    if [ -z "$release_tag" ]; then
+        echo "Release tag cannot be empty. Please check return value of \`go run buildscripts/gen-ldflags.go\`"
+        exit 1;
+    fi
+
+    # Extract release string.
+    release_str=$(echo $MC_RELEASE | tr '[:upper:]' '[:lower:]')
+
+    # Verify release string.
+    if [ -z "$release_str" ]; then
+        echo "Release string cannot be empty. Please set \`MC_RELEASE\` env variable."
+        exit 1;
+    fi
+
+    # List of supported architectures
+    SUPPORTED_OSARCH='linux/386 linux/amd64 linux/arm windows/386 windows/amd64 darwin/amd64'
+}
+
+go_build() {
+    local osarch=$1
+    os=$(echo $osarch | cut -f1 -d'/')
+    arch=$(echo $osarch | cut -f2 -d'/')
+    package=$(go list -f '{{.ImportPath}}')
+    echo -n "-->"
+    printf "%15s:%s\n" "${osarch}" "${package}"
+    GO15VENDOREXPERIMENT=1 GOOS=$os GOARCH=$arch go build --ldflags "${LDFLAGS}" -o $release_str/$os-$arch/$(basename $package).$release_tag
+}
+
+main() {
+    # Build releases.
+    echo "Executing $release_str builds for OS: ${SUPPORTED_OSARCH}"
+    for osarch in ${SUPPORTED_OSARCH}; do
+        go_build ${osarch}
+    done
+}
+
+# Run main.
+_init && main

buildscripts/gen-ldflags.go

@@ -37,7 +37,7 @@ func genLDFlags(version string) string {
 
 // genReleaseTag prints release tag to the console for easy git tagging.
 func releaseTag(version string) string {
-	relPrefix := "UNOFFICIAL"
+	relPrefix := "DEVELOPMENT"
 	if prefix := os.Getenv("MINIO_RELEASE"); prefix != "" {
 		relPrefix = prefix
 	}