Merge branch 'jk/common-main'

There are certain house-keeping tasks that need to be performed at
the very beginning of any Git program, and programs that are not
built-in commands had to do them exactly the same way as "git"
potty does.  It was easy to make mistakes in one-off standalone
programs (like test helpers).  A common "main()" function that
calls cmd_main() of individual program has been introduced to
make it harder to make mistakes.

* jk/common-main:
  mingw: declare main()'s argv as const
  common-main: call git_setup_gettext()
  common-main: call restore_sigpipe_to_default()
  common-main: call sanitize_stdfds()
  common-main: call git_extract_argv0_path()
  add an extra level of indirection to main()

imap-send.c

@@ -1495,16 +1495,12 @@ static int curl_append_msgs_to_imap(struct imap_server_conf *server,
 }
 #endif
 
-int main(int argc, char **argv)
+int cmd_main(int argc, const char **argv)
 {
 	struct strbuf all_msgs = STRBUF_INIT;
 	int total;
 	int nongit_ok;
 
-	git_extract_argv0_path(argv[0]);
-
-	git_setup_gettext();
-
 	setup_git_directory_gently(&nongit_ok);
 	git_imap_config();