BUG:427 trycompile target must be exe

Source/cmGlobalGenerator.cxx

@@ -483,7 +483,13 @@ int cmGlobalGenerator::TryCompile(const char *, const char *bindir,
     makeCommand += " ";
     makeCommand += target;
 #if defined(_WIN32) || defined(__CYGWIN__)
-    makeCommand += ".exe";
+    std::string tmp = target;
+    // if the target does not already end in . something 
+    // then assume .exe
+    if(tmp.size() < 4 || tmp[tmp.size()-4] != '.')
+      {
+      makeCommand += ".exe";
+      }
 #endif // WIN32
     }
   else