Merge branch 'jk/tighten-alloc'

Update various codepaths to avoid manually-counted malloc().

* jk/tighten-alloc: (22 commits)
  ewah: convert to REALLOC_ARRAY, etc
  convert ewah/bitmap code to use xmalloc
  diff_populate_gitlink: use a strbuf
  transport_anonymize_url: use xstrfmt
  git-compat-util: drop mempcpy compat code
  sequencer: simplify memory allocation of get_message
  test-path-utils: fix normalize_path_copy output buffer size
  fetch-pack: simplify add_sought_entry
  fast-import: simplify allocation in start_packfile
  write_untracked_extension: use FLEX_ALLOC helper
  prepare_{git,shell}_cmd: use argv_array
  use st_add and st_mult for allocation size computation
  convert trivial cases to FLEX_ARRAY macros
  use xmallocz to avoid size arithmetic
  convert trivial cases to ALLOC_ARRAY
  convert manual allocations to argv_array
  argv-array: add detach function
  add helpers for allocating flex-array structs
  harden REALLOC_ARRAY and xcalloc against size_t overflow
  tree-diff: catch integer overflow in combine_diff_path allocation
  ...

builtin/mktree.c

@@ -19,16 +19,17 @@ static int alloc, used;
 static void append_to_tree(unsigned mode, unsigned char *sha1, char *path)
 {
 	struct treeent *ent;
-	int len = strlen(path);
+	size_t len = strlen(path);
 	if (strchr(path, '/'))
 		die("path %s contains slash", path);
 
-	ALLOC_GROW(entries, used + 1, alloc);
-	ent = entries[used++] = xmalloc(sizeof(**entries) + len + 1);
+	FLEX_ALLOC_MEM(ent, name, path, len);
 	ent->mode = mode;
 	ent->len = len;
 	hashcpy(ent->sha1, sha1);
-	memcpy(ent->name, path, len+1);
+
+	ALLOC_GROW(entries, used + 1, alloc);
+	entries[used++] = ent;
 }
 
 static int ent_compare(const void *a_, const void *b_)