Fix deheader warnings

Prior to this commit the output of deheader was:
	remove <stdlib.h> from ./jsmn.c
	in ./example/jsondump.c, realloc() portability requires <unistd.h>.
	in ./example/simple.c, strtol() portability requires <stdlib.h>.
	saw 4 files, 16 includes, 1 removable

1 files changed, 0 insertions, 2 deletions

diff --git a/jsmn.c b/jsmn.c
index 2809669b3..bbf013de4 100644
--- a/jsmn.c
+++ b/jsmn.c
@@ -1,5 +1,3 @@
-#include <stdlib.h>
-
 #include "jsmn.h"
 
 /**