alloc: write out allocator definitions

Because the allocator functions for tree, blobs, etc are all
very similar, we originally used a macro to avoid repeating
ourselves. Since the prior commit, though, the heavy lifting
is done by an inline helper function.  The macro does still
save us a few lines, but at some readability cost.  It
obfuscates the function definitions (and makes them hard to
find via grep).

Much worse, though, is the fact that it isn't used
consistently for all allocators. Somebody coming later may
be tempted to modify DEFINE_ALLOCATOR, but they would miss
alloc_commit_node, which is treated specially.

Let's just drop the macro and write everything out
explicitly.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

alloc.c

@@ -18,13 +18,6 @@
 
 #define BLOCKING 1024
 
-#define DEFINE_ALLOCATOR(name, type)				\
-static struct alloc_state name##_state;				\
-void *alloc_##name##_node(void)					\
-{								\
-	return alloc_node(&name##_state, sizeof(type));		\
-}
-
 union any_object {
 	struct object object;
 	struct blob blob;
@@ -55,10 +48,33 @@ static inline void *alloc_node(struct alloc_state *s, size_t node_size)
 	return ret;
 }
 
-DEFINE_ALLOCATOR(blob, struct blob)
+static struct alloc_state blob_state;
-DEFINE_ALLOCATOR(tree, struct tree)
+void *alloc_blob_node(void)
-DEFINE_ALLOCATOR(tag, struct tag)
+{
-DEFINE_ALLOCATOR(object, union any_object)
+	struct blob *b = alloc_node(&blob_state, sizeof(struct blob));
+	return b;
+}
+
+static struct alloc_state tree_state;
+void *alloc_tree_node(void)
+{
+	struct tree *t = alloc_node(&tree_state, sizeof(struct tree));
+	return t;
+}
+
+static struct alloc_state tag_state;
+void *alloc_tag_node(void)
+{
+	struct tag *t = alloc_node(&tag_state, sizeof(struct tag));
+	return t;
+}
+
+static struct alloc_state object_state;
+void *alloc_object_node(void)
+{
+	struct object *obj = alloc_node(&object_state, sizeof(union any_object));
+	return obj;
+}
 
 static struct alloc_state commit_state;