fix #477: remove redundant int32_t macro from d_math.h

pd/src/d_math.c

@@ -67,14 +67,6 @@ static void clip_setup(void)
 #define DUMTAB1SIZE 256
 #define DUMTAB2SIZE 1024
 
-#ifdef MSW
- typedef __int32 int32_t; /* use MSVC's internal type */
-#elif defined(IRIX)
- typedef long int32_t;  /* a data type that has 32 bits */
-#else
-# include <stdint.h>  /* this is where int32_t is defined in C99 */
-#endif
-
 static float rsqrt_exptab[DUMTAB1SIZE], rsqrt_mantissatab[DUMTAB2SIZE];
 
 static void init_rsqrt(void)