Fixes for Irix compatibility.

Fix several long standing irix compiler warnings.

src/ATC/ATC.hxx

@@ -24,7 +24,7 @@
 
 // Possible types of ATC type that the radios may be tuned to.
 // INVALID implies not tuned in to anything.
-typedef enum atc_type {
+enum atc_type {
     INVALID,
     ATIS,
     GROUND,

src/Cockpit/panel.hxx

@@ -473,7 +473,7 @@ private:
 class FGTextLayer : public FGInstrumentLayer
 {
 public:
-  typedef enum ChunkType {
+  enum ChunkType {
     TEXT,
     TEXT_VALUE,
     DOUBLE_VALUE

src/Main/logger.cxx

@@ -5,9 +5,11 @@
 
 #include "logger.hxx"
 
-#include <fstream>
+#include STL_FSTREAM
+#ifndef SG_HAVE_NATIVE_SGI_COMPILERS
 SG_USING_STD(ofstream);
 SG_USING_STD(endl);
+#endif
 
 #include <string>
 SG_USING_STD(string);

src/Main/logger.hxx

@@ -19,8 +19,10 @@
 #include <simgear/misc/exception.hxx>
 #include <simgear/misc/props.hxx>
 
+#ifndef SG_HAVE_NATIVE_SGI_COMPILERS
 #include <iostream>
 SG_USING_STD(ostream);
+#endif
 
 #include <vector>
 SG_USING_STD(vector);

src/WeatherCM/FGSnowRain.h

@@ -52,7 +52,7 @@ HISTORY
 /****************************************************************************/
 /* DEFINES								    */
 /****************************************************************************/
-typedef enum SnowRainType
+enum SnowRainType
 {
     Rain,
     Snow,