malloc.h is not standard, even on sparc

Index: cextern/cfitsio/lib/eval_l.c
--- cextern/cfitsio/lib/eval_l.c.orig
+++ cextern/cfitsio/lib/eval_l.c
@@ -857,11 +857,7 @@ static const flex_int16_t yy_chk[472] =
 #include <math.h>
 #include <string.h>
 #include <ctype.h>
-#ifdef sparc
-#include <malloc.h>
-#else
 #include <stdlib.h>
-#endif
 #include "eval_defs.h"
 #include "eval_tab.h"
 
