mpack: Fix conflicting malloc definition

Use stdlib.h for malloc(), getenv() and realloc(). Fixes the following
build failure:

unixos.c:42:14: error: conflicting types for 'malloc'
 extern char *malloc();
              ^
Makefile:168: recipe for target 'unixos.o' failed
make[3]: *** [unixos.o] Error 1

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>

utils/mpack/patches/001-use-stdlib.patch

@@ -0,0 +1,34 @@
+Index: mpack-1.6/unixos.c
+===================================================================
+--- mpack-1.6.orig/unixos.c
++++ mpack-1.6/unixos.c
+@@ -25,6 +25,7 @@
+ #include <stdio.h>
+ #include <ctype.h>
+ #include <string.h>
++#include <stdlib.h>
+ #include <errno.h>
+ #include <sys/types.h>
+ #include <sys/param.h>
+@@ -39,8 +40,6 @@
+ #endif
+ 
+ extern int errno;
+-extern char *malloc();
+-extern char *getenv();
+ 
+ int overwrite_files = 0;
+ int didchat;
+Index: mpack-1.6/xmalloc.c
+===================================================================
+--- mpack-1.6.orig/xmalloc.c
++++ mpack-1.6/xmalloc.c
+@@ -24,7 +24,7 @@
+  */
+ #include <stdio.h>
+ #include <string.h>
+-extern char *malloc(), *realloc();
++#include <stdlib.h>
+ 
+ char *xmalloc (int size)
+ {