Add static check for `MRB_USE_FLOAT` and `MRB_WITHOUT_FLOAT`.
/* exclude floating point numbers */
//#define MRB_WITHOUT_FLOAT
+#if defined(MRB_USE_FLOAT) && defined(MRB_WITHOUT_FLOAT)
+#error Cannot define MRB_USE_FLOAT and MRB_WITHOUT_FLOAT at the same time
+#endif
+
/* stop inlining floating point numbers in mrb_value (effective only with MRB_WORD_BOXING)*/
/* floating numbers are rounded to fit in 30 bits (float) and 62 bits respectively, */
/* by inlining. If you need full precision of floating numbers on the platform, */
