diff --git a/src/Makefile b/src/Makefile
index 0a25e92fb..1616700f2 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -3,16 +3,16 @@
 ## License.....: MIT
 ##
 
-SHARED                  := 0
+SHARED                  ?= 0
 DEBUG                   := 0
 PRODUCTION              := 0
 PRODUCTION_VERSION      := v6.0.0
-ENABLE_CUBIN            := 1
-ENABLE_BRAIN            := 1
-USE_SYSTEM_LZMA         := 0
-USE_SYSTEM_ZLIB         := 0
-USE_SYSTEM_OPENCL       := 0
-USE_SYSTEM_XXHASH       := 0
+ENABLE_CUBIN            ?= 1
+ENABLE_BRAIN            ?= 1
+USE_SYSTEM_LZMA         ?= 0
+USE_SYSTEM_ZLIB         ?= 0
+USE_SYSTEM_OPENCL       ?= 0
+USE_SYSTEM_XXHASH       ?= 0
 
 ##
 ## Detect Operating System