diff --git a/Makefile.conf b/Makefile.conf
index d7d171fb..414ad310 100644
--- a/Makefile.conf
+++ b/Makefile.conf
@@ -100,11 +100,8 @@ ifeq ($(BUILD_FOR),OS/390)
     CFLAGS+= -I/usr/include
     CFLAGS+= -DZOS -D_XOPEN_SOURCE=600 -D_POSIX_C_SOURCE=200112L -qlanglvl=NOLIBEXT
 else ifeq ($(BUILD_FOR),Linux)
-    CFLAGS+= -DUNIX 
     CFLAGS+=-fPIC -fstrict-aliasing -fdiagnostics-color=auto
 else ifeq ($(BUILD_FOR),Darwin)
-    CFLAGS+= -DUNIX 
-    CFLAGS+= -DDARWIN 
     CFLAGS+=-pthread -fPIC -fstrict-aliasing -fcolor-diagnostics
 endif