temp.c:4:1: warning: incompatible implicit declaration of built-in function ‘exit’

--- Makefile.in
+++ Makefile.in
@@ -269,6 +269,7 @@
 #
 config.h:	
 	echo '#include <stdio.h>' >temp.c
+	echo '#include <stdlib.h>' >>temp.c
 	echo 'int main(){printf(' >>temp.c
 	echo '"#define SQLITE_PTR_SZ %d",sizeof(char*));' >>temp.c
 	echo 'exit(0);}' >>temp.c