diff -up ext/php/phpext.c.php53 ext/php/phpext.c
--- ext/php/phpext.c.php53	2009-07-14 08:03:44.000000000 +0200
+++ ext/php/phpext.c	2009-07-14 08:08:36.000000000 +0200
@@ -21,7 +21,7 @@
 static double zero()    { return 0.0; }
 static double one() { return 1.0; }
 static double inf() { return one() / zero(); }
-static double nan() { return zero() / zero(); }
+static double mynan() { return zero() / zero(); }
 
 /* {{{ syck_functions[]
  *
@@ -220,7 +220,7 @@ php_syck_handler(p, n)
             }
             else if ( strcmp( n->type_id, "float#nan" ) == 0 )
             {
-                ZVAL_DOUBLE( o, nan() );
+                ZVAL_DOUBLE( o, mynan() );
             }
             else if ( strcmp( n->type_id, "float#inf" ) == 0 )
             {
diff -up ext/php/php_syck.h.php53 ext/php/php_syck.h