diff --git a/tools/Makefile b/tools/Makefile
index 1ac9c8cb..75665251 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -21,7 +21,7 @@ else
   endif
 endif
 ifeq ($(HOST_OS),Windows)
-  CFLAGS += -DWIN32 -D_WIN32 -D__CYGWIN__
+  CFLAGS += -DWIN32 -D_WIN32
 endif
 
 BUILD_PROGRAMS := $(ALL_PROGRAMS)
diff --git a/tools/audiofile/Makefile b/tools/audiofile/Makefile
index 5e204324..82ca0872 100644
--- a/tools/audiofile/Makefile
+++ b/tools/audiofile/Makefile
@@ -13,7 +13,7 @@ else
   endif
 endif
 ifeq ($(HOST_OS),Windows)
-  CFLAGS += -DWIN32 -D_WIN32 -D__CYGWIN__
+  CFLAGS += -DWIN32 -D_WIN32
 endif
 
 libaudiofile.a: audiofile.o
diff --git a/tools/sdk-tools/adpcm/Makefile b/tools/sdk-tools/adpcm/Makefile
index 9fee76d1..7a773fcc 100644
--- a/tools/sdk-tools/adpcm/Makefile
+++ b/tools/sdk-tools/adpcm/Makefile
@@ -19,7 +19,7 @@ else
   endif
 endif
 ifeq ($(HOST_OS),Windows)
-  NATIVE_CFLAGS += -DWIN32 -D_WIN32 -D__CYGWIN__
+  NATIVE_CFLAGS += -DWIN32 -D_WIN32
 endif
 
 default: native
diff --git a/tools/sdk-tools/tabledesign/Makefile b/tools/sdk-tools/tabledesign/Makefile
index afd0a92e..00eaa449 100644
--- a/tools/sdk-tools/tabledesign/Makefile
+++ b/tools/sdk-tools/tabledesign/Makefile
@@ -19,7 +19,7 @@ else
   endif
 endif
 ifeq ($(HOST_OS),Windows)
-  NATIVE_CFLAGS += -DWIN32 -D_WIN32 -D__CYGWIN__
+  NATIVE_CFLAGS += -DWIN32 -D_WIN32
 endif
 
 LDFLAGS := -lm -laudiofile