diff --git a/hwaccess.c b/hwaccess.c
index aede7e3..2bf6f42 100644
--- a/hwaccess.c
+++ b/hwaccess.c
@@ -37,9 +37,21 @@
 #error "Unknown operating system"
 #endif
 
-#define USE_IOPL	(IS_LINUX || IS_MACOSX || defined(__NetBSD__) || defined(__OpenBSD__))
-#define USE_DEV_IO	(defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__DragonFly__))
-#define USE_IOPERM	(defined(__gnu_hurd__))
+#if IS_LINUX || IS_MACOSX || defined(__NetBSD__) || defined(__OpenBSD__)
+#define USE_IOPL 1
+#else
+#define USE_IOPL 0
+#endif
+#if defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__DragonFly__)
+#define USE_DEV_IO 1
+#else
+#define USE_DEV_IO 0
+#endif
+#if defined(__gnu_hurd__)
+#define USE_IOPERM 1
+#else
+#define USE_IOPERM 0
+#endif
 
 #if USE_IOPERM
 #include <sys/io.h>
diff --git a/platform.h b/platform.h
index c5a52ef..b2fdcd0 100644
--- a/platform.h
+++ b/platform.h
@@ -25,9 +25,21 @@
 #define __PLATFORM_H__ 1
 
 // Helper defines for operating systems
-#define IS_LINUX	(defined(__gnu_linux__) || defined(__linux__))
-#define IS_MACOSX	(defined(__APPLE__) && defined(__MACH__)) /* yes, both. */
-#define IS_WINDOWS	(defined(_WIN32) || defined(_WIN64) || defined(__WIN32__) || defined(__WINDOWS__))
+#if defined(__gnu_linux__) || defined(__linux__)
+#define IS_LINUX 1
+#else
+#define IS_LINUX 0
+#endif
+#if defined(__APPLE__) && defined(__MACH__) /* yes, both. */
+#define IS_MACOSX 1
+#else
+#define IS_MACOSX 0
+#endif
+#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__)