Fixes everywhere...

+ utils: now contain a hash prototype.
+ utils: contains default cmp for exact matched comparisons.
+ utils: using uintptr_t instead of void *.
+ array: pusht changed to push_t.
+ array: array_i_t now returns a pointer to the array.
+ array: added take and give functions.
+ heap:  using utils_cmp_r and passing array_elm as parameter (elm size).
+ string:removed extra '\0' from some functions.
+ rules: passing cflags to ld (to preserve -g/-lto...).