Modified preprocessor directives to be better.

src/engine.c

@@ -24,11 +24,9 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 #ifdef __HAIKU__
 #include <FindDirectory.h>
-#else
-#ifndef _WIN32
+#elif !defined(_WIN32)
 #include <pwd.h>
 #endif
-#endif
 
 #include "SDL.h"
 
@@ -216,7 +214,7 @@ void engine_setupConfigDirectory()
 		engine_showError(2, dir);
 
 	snprintf(engine.configDirectory, PATH_MAX, "%s/", dir);
-#elif __HAIKU__
+#elif defined(__HAIKU__)
 	subdir = "starfighter";
 
 	char path[PATH_MAX];