fix mingw

simgear/misc/sg_path.cxx

@@ -490,7 +490,7 @@ std::string SGPath::realpath() const
     // This means relative paths cannot be used on Mac OS <= 10.5
     return path;
 #else
-  #if defined(_MSC_VER)
+  #if defined(_MSC_VER) /*for MS compilers */ || defined(_WIN32) /*needed for non MS windows compilers like MingW*/
     // with absPath NULL, will allocate, and ignore length
     char *buf = _fullpath( NULL, path.c_str(), _MAX_PATH );
   #else

simgear/sound/sample_group.cxx

@@ -34,6 +34,7 @@
 #include "sample_group.hxx"
 
 using std::string;
+using std::isnan;
 
 bool isNaN(float *v) {
    return (isnan(v[0]) || isnan(v[1]) || isnan(v[2]));