scripts: able to set XC_ARCH/OS manually

scripts/build.sh

@@ -15,6 +15,12 @@ cd $DIR
 GIT_COMMIT=$(git rev-parse HEAD)
 GIT_DIRTY=$(test -n "`git status --porcelain`" && echo "+CHANGES" || true)
 
+# If its dev mode, only build for ourself
+if [ "${TF_DEV}x" != "x" ]; then
+    XC_OS=${XC_OS:-$(go env GOOS)}
+    XC_ARCH=${XC_ARCH:-$(go env GOARCH)}
+fi
+
 # Determine the arch/os combos we're building for
 XC_ARCH=${XC_ARCH:-"386 amd64 arm"}
 XC_OS=${XC_OS:-linux darwin windows freebsd openbsd}
@@ -29,12 +35,6 @@ rm -f bin/*
 rm -rf pkg/*
 mkdir -p bin/
 
-# If its dev mode, only build for ourself
-if [ "${TF_DEV}x" != "x" ]; then
-    XC_OS=$(go env GOOS)
-    XC_ARCH=$(go env GOARCH)
-fi
-
 # Build!
 echo "==> Building..."
 gox \