diff --git a/simgear/compiler.h b/simgear/compiler.h
index b168252d..ed3f9f1b 100644
--- a/simgear/compiler.h
+++ b/simgear/compiler.h
@@ -324,7 +324,7 @@
 #endif // Native SGI compilers
 
 
-#if defined ( sun )
+#if defined (__sun)
 #  include <strings.h>
 #  include <memory.h>
 #  if defined ( __cplusplus )
diff --git a/simgear/timing/sg_time.cxx b/simgear/timing/sg_time.cxx
index 64472507..efa59c7d 100644
--- a/simgear/timing/sg_time.cxx
+++ b/simgear/timing/sg_time.cxx
@@ -530,7 +530,7 @@ time_t sgTimeGetGMT(int year, int month, int day, int hour, int min, int sec)
 #else // ! defined ( MK_TIME_IS_GMT )
 
     // timezone seems to work as a proper offset for Linux & Solaris
-#   if defined( __linux__ ) || defined( __sun__ ) ||defined(__CYGWIN__)
+#   if defined( __linux__ ) || defined(__sun) ||defined(__CYGWIN__)
 #       define TIMEZONE_OFFSET_WORKS 1
 #   endif