diff --git a/Makefile b/Makefile
index d628f7d..1887846 100644
--- a/Makefile
+++ b/Makefile
@@ -196,6 +196,12 @@
 $(call mark_unsupported,$(DEPENDS_ON_LIBUSB1) $(DEPENDS_ON_LIBFTDI) $(DEPENDS_ON_LIBJAYLINK))
 endif
 
+ifeq ($(TARGET_OS), $(filter $(TARGET_OS), MinGW Cygwin))
+FEATURE_CFLAGS += -D'IS_WINDOWS=1'
+else
+FEATURE_CFLAGS += -D'IS_WINDOWS=0'
+endif
+
 # FIXME: Should we check for Cygwin/MSVC as well?
 ifeq ($(TARGET_OS), MinGW)
 EXEC_SUFFIX := .exe
diff --git a/meson.build b/meson.build
index 28f15a0..29a57a9 100644
--- a/meson.build
+++ b/meson.build
@@ -36,6 +36,12 @@
   add_project_arguments('-D__FLASHROM_BIG_ENDIAN__=1', language : 'c')
 endif
 
+if host_machine.system() in ['cygwin', 'windows']
+  add_project_arguments('-DIS_WINDOWS=1', language : 'c')
+else
+  add_project_arguments('-DIS_WINDOWS=0', language : 'c')
+endif
+
 # get defaults from configure
 config_atahpt = get_option('config_atahpt')
 config_atapromise = get_option('config_atapromise')
diff --git a/platform.h b/platform.h
index 34a56ab..e0f8a73 100644
--- a/platform.h
+++ b/platform.h
@@ -20,13 +20,6 @@
 #ifndef __PLATFORM_H__
 #define __PLATFORM_H__ 1
 
-// Helper defines for operating systems
-#if defined(_WIN32) || defined(_WIN64) || defined(__WIN32__) || defined(__WINDOWS__)
-#define IS_WINDOWS 1
-#else
-#define IS_WINDOWS 0
-#endif
-
 // Likewise for target architectures
 #if defined (__i386__) || defined (__x86_64__) || defined(__amd64__)
 	#define IS_X86 1