Fix prototype

libc/stdlib/gcvt.c

@@ -1,9 +1,9 @@
-
+#include <stdio.h>
 #include <stdlib.h>
 
 #ifdef __UCLIBC_HAS_FLOATS__
 #define MAX_NDIGIT 17
-char * gcvt(double number, size_t ndigit, char* buf)
+char *gcvt (double number, int ndigit, char *buf)
 {
     sprintf(buf, "%.*g", (ndigit > MAX_NDIGIT)? MAX_NDIGIT : ndigit, number);
     return buf;