eina: fix missing header

This caused functions from eina_util to be undefined at compile time.
The compiler would make implicit casts of return values into ints,
which had major side effects (e.g. segfault edje_cc)

@fix

src/lib/eina/eina_file_common.h

@@ -23,6 +23,7 @@
 #include "eina_tmpstr.h"
 #include "eina_lock.h"
 #include "eina_list.h"
+#include "eina_util.h"
 
 #define EINA_FILE_MAGIC 0xFEEDBEEF