Attempt to fix the bcmath build

Author: TimWolla

ext/standard/php_math_round_mode.h

@@ -15,6 +15,8 @@
    +----------------------------------------------------------------------+
 */
 
+#include "php.h"
+
 /* Define rounding modes (all are round-to-nearest) */
 #ifndef PHP_ROUND_HALF_UP
 #define PHP_ROUND_HALF_UP        0x01    /* Arithmetic rounding, up == away from zero */