Replace #pragma once with #ifndef #define #endif logic because #pragma once does not work cleanly on OSX

include/logfile.h

@@ -3,7 +3,8 @@
  * License.....: MIT
  */
 
-#pragma once
+#ifndef _LOGFILE_H
+#define _LOGFILE_H
 
 #include <stdio.h>
 #include <stdlib.h>
@@ -14,3 +15,5 @@ char *logfile_generate_topid (void);
 char *logfile_generate_subid (void);
 
 void logfile_append (const char *fmt, ...);
+
+#endif // _LOGFILE_H