diff --git a/make/defs.mk b/make/defs.mk
index b84083bc..d558c33f 100644
--- a/make/defs.mk
+++ b/make/defs.mk
@@ -162,23 +162,23 @@ ifeq ($(TARGET),mingw)
   CROSS_TOOL_DIR      ?= /opt/cross-tools
   CROSS_TOOL_BIN_PREFIX ?= $(CROSS_TOOL_DIR)/bin/i686-pc-mingw32-
  endif
-GCC                    = $(CROSS_TOOL_BIN_PREFIX)gcc
-GPP                    = $(CROSS_TOOL_BIN_PREFIX)g++
-STRIP                  = $(CROSS_TOOL_BIN_PREFIX)strip
-RANLIB                 = $(CROSS_TOOL_BIN_PREFIX)ranlib
-AR                     = $(CROSS_TOOL_BIN_PREFIX)ar
-WINDRES                = $(CROSS_TOOL_BIN_PREFIX)windres
+GCC                   ?= $(CROSS_TOOL_BIN_PREFIX)gcc
+GPP                   ?= $(CROSS_TOOL_BIN_PREFIX)g++
+STRIP                 ?= $(CROSS_TOOL_BIN_PREFIX)strip
+RANLIB                ?= $(CROSS_TOOL_BIN_PREFIX)ranlib
+AR                    ?= $(CROSS_TOOL_BIN_PREFIX)ar
+WINDRES               ?= $(CROSS_TOOL_BIN_PREFIX)windres
 BUILD_LDFLAGS         += -lws2_32
-USE_GFILTER            = false
+USE_GFILTER           ?= false
 MS_LD                 ?= wine $(HOME)/local/mingw/packages/msvcpp/bin/LIB.EXE
 LD                     = $(GPP)
 else
-GCC                    = gcc
-GPP                    = g++
-STRIP                  = strip
+GCC                   ?= gcc
+GPP                   ?= g++
+STRIP                 ?= strip
 LD                     = $(GPP)
-RANLIB                 = ranlib
-AR                     = ar
+RANLIB                ?= ranlib
+AR                    ?= ar
 endif
 
 # makefile helpers