diff --git a/Makefile b/Makefile
index cd8d6b2..bcf3403 100644
--- a/Makefile
+++ b/Makefile
@@ -5,13 +5,13 @@
 MAJOR_VERSION = 4
 MINOR_VERSION = 6
 SUBMINOR_VERSION = 0
-VERSION = $(MAJOR_VERSION).$(MINOR_VERSION).$(SUBMINOR_VERSION)
+VERSION ?= $(MAJOR_VERSION).$(MINOR_VERSION).$(SUBMINOR_VERSION)
 
 LIBOBJCLIBNAME=objc
 LIBOBJC=libobjc
 LIBOBJCXX=libobjcxx
 
-SILENT=@
+SILENT ?= @
 
 CFLAGS += -std=gnu99 -fPIC -fexceptions
 CFLAGS += -Wno-deprecated-objc-isa-usage