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
  ...

compat/mingw.c

@@ -810,7 +810,7 @@ static const char *quote_arg(const char *arg)
 		return arg;
 
 	/* insert \ where necessary */
-	d = q = xmalloc(len+n+3);
+	d = q = xmalloc(st_add3(len, n, 3));
 	*d++ = '"';
 	while (*arg) {
 		if (*arg == '"')
@@ -893,7 +893,7 @@ static char **get_path_split(void)
 	if (!n)
 		return NULL;
 
-	path = xmalloc((n+1)*sizeof(char *));
+	ALLOC_ARRAY(path, n + 1);
 	p = envpath;
 	i = 0;
 	do {
@@ -978,7 +978,7 @@ static wchar_t *make_environment_block(char **deltaenv)
 		i++;
 
 	/* copy the environment, leaving space for changes */
-	tmpenv = xmalloc((size + i) * sizeof(char*));
+	ALLOC_ARRAY(tmpenv, size + i);
 	memcpy(tmpenv, environ, size * sizeof(char*));
 
 	/* merge supplied environment changes into the temporary environment */
@@ -1069,7 +1069,7 @@ static pid_t mingw_spawnve_fd(const char *cmd, const char **argv, char **deltaen
 			free(quoted);
 	}
 
-	wargs = xmalloc((2 * args.len + 1) * sizeof(wchar_t));
+	wargs = xmalloc_array(st_add(st_mult(2, args.len), 1), sizeof(wchar_t));
 	xutftowcs(wargs, args.buf, 2 * args.len + 1);
 	strbuf_release(&args);
 
@@ -1168,7 +1168,7 @@ static int try_shell_exec(const char *cmd, char *const *argv)
 		int argc = 0;
 		const char **argv2;
 		while (argv[argc]) argc++;
-		argv2 = xmalloc(sizeof(*argv) * (argc+1));
+		ALLOC_ARRAY(argv2, argc + 1);
 		argv2[0] = (char *)cmd;	/* full path to the script file */
 		memcpy(&argv2[1], &argv[1], sizeof(*argv) * argc);
 		pid = mingw_spawnv(prog, argv2, 1);