diff --git a/lib/Makefile.m32 b/lib/Makefile.m32
index 6ddb1215a..c3d1741e8 100644
--- a/lib/Makefile.m32
+++ b/lib/Makefile.m32
@@ -29,7 +29,7 @@ STRIP = strip -g
 ## Nothing more to do below this line!
 
 INCLUDES = -I. -I../include
-CFLAGS = -g -O2 -DMINGW32 -DBUILDING_LIBCURL -DHAVE_LONGLONG
+CFLAGS = -g -O2 -DBUILDING_LIBCURL -DHAVE_LONGLONG
 ifdef SSH2
   INCLUDES += -I"$(LIBSSH2_PATH)/include" -I"$(LIBSSH2_PATH)/win32"
   CFLAGS += -DUSE_LIBSSH2 -DHAVE_LIBSSH2_H
diff --git a/src/Makefile.m32 b/src/Makefile.m32
index ade4e51d4..5e463a9c8 100644
--- a/src/Makefile.m32
+++ b/src/Makefile.m32
@@ -31,7 +31,7 @@ STRIP = strip -s
 ## Nothing more to do below this line!
 
 INCLUDES = -I. -I.. -I../include -I../lib -I$(ZLIB_PATH)
-CFLAGS = -g -O2 -DMINGW32
+CFLAGS = -g -O2
 LDFLAGS =
 COMPILE = $(CC) $(INCLUDES) $(CFLAGS)
 LINK = $(CC) $(CFLAGS) $(LDFLAGS) -o $@