diff --git a/config-mingw.mk b/config-mingw.mk
index a115277a..be8abca1 100644
--- a/config-mingw.mk
+++ b/config-mingw.mk
@@ -20,8 +20,8 @@
 
 # Use make -f Makefile.gcc PREFIX=i686-w64-mingw32-
 # for cross compilation
-CC = $(PREFIX)gcc
-AR = $(PREFIX)ar
+CC ?= $(PREFIX)gcc
+AR ?= $(PREFIX)ar
 E=.exe
 
 CFLAGS=$(CPPFLAGS) -g --std=gnu89 -D_WIN32_WINNT=0x0501 -Isrc/ares/config_win32
diff --git a/config-unix.mk b/config-unix.mk
index 2def593b..862af2d4 100644
--- a/config-unix.mk
+++ b/config-unix.mk
@@ -18,8 +18,8 @@
 # FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 # IN THE SOFTWARE.
 
-CC = $(PREFIX)gcc
-AR = $(PREFIX)ar
+CC ?= $(PREFIX)gcc
+AR ?= $(PREFIX)ar
 E=
 CFLAGS=--std=gnu89 -g
 CPPFLAGS += -Isrc/ev