git-compat-util: move alloc macros to git-compat-util.h

alloc_nr, ALLOC_GROW, and ALLOC_GROW_BY are commonly used macros for
dynamic array allocation. Moving these macros to git-compat-util.h with
the other alloc macros focuses alloc.[ch] to allocation for Git objects
and additionally allows us to remove inclusions to alloc.h from files
that solely used the above macros.

Signed-off-by: Calvin Wan <calvinwan@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

alloc.h

@@ -17,79 +17,4 @@ void *alloc_object_node(struct repository *r);
 struct alloc_state *allocate_alloc_state(void);
 void clear_alloc_state(struct alloc_state *s);
 
-#define alloc_nr(x) (((x)+16)*3/2)
-
-/**
- * Dynamically growing an array using realloc() is error prone and boring.
- *
- * Define your array with:
- *
- * - a pointer (`item`) that points at the array, initialized to `NULL`
- *   (although please name the variable based on its contents, not on its
- *   type);
- *
- * - an integer variable (`alloc`) that keeps track of how big the current
- *   allocation is, initialized to `0`;
- *
- * - another integer variable (`nr`) to keep track of how many elements the
- *   array currently has, initialized to `0`.
- *
- * Then before adding `n`th element to the item, call `ALLOC_GROW(item, n,
- * alloc)`.  This ensures that the array can hold at least `n` elements by
- * calling `realloc(3)` and adjusting `alloc` variable.
- *
- * ------------
- * sometype *item;
- * size_t nr;
- * size_t alloc
- *
- * for (i = 0; i < nr; i++)
- * 	if (we like item[i] already)
- * 		return;
- *
- * // we did not like any existing one, so add one
- * ALLOC_GROW(item, nr + 1, alloc);
- * item[nr++] = value you like;
- * ------------
- *
- * You are responsible for updating the `nr` variable.
- *
- * If you need to specify the number of elements to allocate explicitly
- * then use the macro `REALLOC_ARRAY(item, alloc)` instead of `ALLOC_GROW`.
- *
- * Consider using ALLOC_GROW_BY instead of ALLOC_GROW as it has some
- * added niceties.
- *
- * DO NOT USE any expression with side-effect for 'x', 'nr', or 'alloc'.
- */
-#define ALLOC_GROW(x, nr, alloc) \
-	do { \
-		if ((nr) > alloc) { \
-			if (alloc_nr(alloc) < (nr)) \
-				alloc = (nr); \
-			else \
-				alloc = alloc_nr(alloc); \
-			REALLOC_ARRAY(x, alloc); \
-		} \
-	} while (0)
-
-/*
- * Similar to ALLOC_GROW but handles updating of the nr value and
- * zeroing the bytes of the newly-grown array elements.
- *
- * DO NOT USE any expression with side-effect for any of the
- * arguments.
- */
-#define ALLOC_GROW_BY(x, nr, increase, alloc) \
-	do { \
-		if (increase) { \
-			size_t new_nr = nr + (increase); \
-			if (new_nr < nr) \
-				BUG("negative growth in ALLOC_GROW_BY"); \
-			ALLOC_GROW(x, new_nr, alloc); \
-			memset((x) + nr, 0, sizeof(*(x)) * (increase)); \
-			nr = new_nr; \
-		} \
-	} while (0)
-
 #endif