Clang buildfixes

Building with clang took a few very small changes. The change to
helper/log.h is because clang doesn't like an expression where the
result is unused. In helper/system.h, I just defined true and false
since clang doesn't have them builtin.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>

src/helper/log.h

@@ -111,7 +111,12 @@ extern int debug_level;
 #define LOG_LEVEL_IS(FOO)  ((debug_level) >= (FOO))
 
 #define LOG_DEBUG(expr ...) \
-		((debug_level >= LOG_LVL_DEBUG) ? log_printf_lf (LOG_LVL_DEBUG, __FILE__, __LINE__, __FUNCTION__, expr) , 0 : 0)
+		do { \
+			if (debug_level >= LOG_LVL_DEBUG) \
+				log_printf_lf(LOG_LVL_DEBUG, \
+					__FILE__, __LINE__, __func__, \
+					expr); \
+		} while (0)
 
 #define LOG_INFO(expr ...) \
 		log_printf_lf (LOG_LVL_INFO, __FILE__, __LINE__, __FUNCTION__, expr)

src/helper/system.h

@@ -85,4 +85,9 @@
 #include <fcntl.h>
 #endif
 
+#ifndef true
+#define true	1
+#define false	0
+#endif
+
 #endif // SYSTEM_H