[flashrom] [PATCH] Fix undefined behavior in OS defines

[Stefan Tauner]

Found by clang (warning introduced in r258128), reported by Idwer.

Signed-off-by: Stefan Tauner <stefan.tauner at alumni.tuwien.ac.at>
---
 platform.h | 22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/platform.h b/platform.h
index c5a52ef..b58c303 100644
--- a/platform.h
+++ b/platform.h
@@ -24,10 +24,24 @@
 #ifndef __PLATFORM_H__
 #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__))
+/* Helper defines for operating systems.
+ * This may seem complicated but the following would be undefined behavior:
+ * #define IS_LINUX	(defined(__gnu_linux__) || defined(__linux__)) */
+#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__)
-- 
Kind regards, Stefan Tauner