Added headless build support

Makefile

@@ -12,6 +12,10 @@ all:
 	$(MAKE) -C $(SRC) unix
 	$(MAKE) dist
 
+headless:
+	$(MAKE) -C $(SRC) unix-headless
+	$(MAKE) dist
+
 win64:
 	$(MAKE) -C $(SRC) win64
 	$(MAKE) dist
@@ -20,6 +24,10 @@ win64-cross:
 	$(MAKE) -C $(SRC) CGO_ENABLED=1 CC=$(CROSSCC) CXX=$(CROSSCXX) win64
 	$(MAKE) dist
 
+win64-headless:
+	$(MAKE) -C $(SRC) win64-headless
+	$(MAKE) dist
+
 dist:
 	mkdir -p $(DIST)
 	mv $(SRC)/streamgoose* $(DIST)/