Refactor - always enable LOG macro. Enhance iolog

src/log.h

@@ -3,17 +3,28 @@
 #include "arch.h"
 #include "config.h"
 
+enum { LL_NONE, LL_ERROR, LL_INFO, LL_DEBUG, LL_VERBOSE_DEBUG };
+void mg_log(const char *fmt, ...) PRINTF_LIKE(1, 2);
+bool mg_log_prefix(int ll, const char *file, int line, const char *fname);
+void mg_log_set(const char *spec);
+void mg_log_set_callback(void (*fn)(const void *, size_t, void *), void *param);
+
+// Let the compiler always see the log invocation in order to check parameters
+// For MG_ENABLE_LOG=0 case, the call will be optimised out, anyway
+
 #if MG_ENABLE_LOG
+
 #define LOG(level, args)                                                   \
   do {                                                                     \
     if (mg_log_prefix((level), __FILE__, __LINE__, __func__)) mg_log args; \
   } while (0)
-enum { LL_NONE, LL_ERROR, LL_INFO, LL_DEBUG, LL_VERBOSE_DEBUG };
-bool mg_log_prefix(int ll, const char *file, int line, const char *fname);
-void mg_log(const char *fmt, ...) PRINTF_LIKE(1, 2);
-void mg_log_set(const char *spec);
-void mg_log_set_callback(void (*fn)(const void *, size_t, void *), void *param);
+
 #else
-#define LOG(level, args) (void) 0
-#define mg_log_set(x) (void) (x)
+
+#define LOG(level, args) \
+  do {                   \
+    (void) level;        \
+    if (0) mg_log args;  \
+  } while (0)
+
 #endif