update-microsoft-git: create barebones builtin

Just do the boilerplate stuff of making a new builtin, including
documentation and integration with git.c.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>

.gitignore

@@ -170,6 +170,7 @@
 /git-unpack-file
 /git-unpack-objects
 /git-update-index
+/git-update-microsoft-git
 /git-update-ref
 /git-update-server-info
 /git-upload-archive

Documentation/git-update-microsoft-git.txt

@@ -0,0 +1,24 @@
+git-update-microsoft-git(1)
+===========================
+
+NAME
+----
+git-update-microsoft-git - Update the installed version of Git
+
+
+SYNOPSIS
+--------
+[verse]
+'git update-microsoft-git'
+
+DESCRIPTION
+-----------
+This version of Git is based on the Microsoft fork of Git, which
+has custom capabilities focused on supporting monorepos. This
+command checks for the latest release of that fork and installs
+it on your machine.
+
+
+GIT
+---
+Part of the linkgit:git[1] suite

Makefile

@@ -1316,6 +1316,7 @@ BUILTIN_OBJS += builtin/tag.o
 BUILTIN_OBJS += builtin/unpack-file.o
 BUILTIN_OBJS += builtin/unpack-objects.o
 BUILTIN_OBJS += builtin/update-index.o
+BUILTIN_OBJS += builtin/update-microsoft-git.o
 BUILTIN_OBJS += builtin/update-ref.o
 BUILTIN_OBJS += builtin/update-server-info.o
 BUILTIN_OBJS += builtin/upload-archive.o

builtin.h

@@ -227,6 +227,7 @@ int cmd_tag(int argc, const char **argv, const char *prefix);
 int cmd_unpack_file(int argc, const char **argv, const char *prefix);
 int cmd_unpack_objects(int argc, const char **argv, const char *prefix);
 int cmd_update_index(int argc, const char **argv, const char *prefix);
+int cmd_update_microsoft_git(int argc, const char **argv, const char *prefix);
 int cmd_update_ref(int argc, const char **argv, const char *prefix);
 int cmd_update_server_info(int argc, const char **argv, const char *prefix);
 int cmd_upload_archive(int argc, const char **argv, const char *prefix);

builtin/update-microsoft-git.c

@@ -0,0 +1,20 @@
+#include "builtin.h"
+#include "repository.h"
+#include "parse-options.h"
+#include "run-command.h"
+
+static int platform_specific_upgrade(void)
+{
+	return 1;
+}
+
+static const char builtin_update_microsoft_git_usage[] =
+	N_("git update-microsoft-git");
+
+int cmd_update_microsoft_git(int argc, const char **argv, const char *prefix)
+{
+	if (argc == 2 && !strcmp(argv[1], "-h"))
+		usage(builtin_update_microsoft_git_usage);
+
+	return platform_specific_upgrade();
+}

git.c

@@ -669,6 +669,7 @@ static struct cmd_struct commands[] = {
 	{ "unpack-file", cmd_unpack_file, RUN_SETUP | NO_PARSEOPT },
 	{ "unpack-objects", cmd_unpack_objects, RUN_SETUP | NO_PARSEOPT },
 	{ "update-index", cmd_update_index, RUN_SETUP },
+	{ "update-microsoft-git", cmd_update_microsoft_git },
 	{ "update-ref", cmd_update_ref, RUN_SETUP },
 	{ "update-server-info", cmd_update_server_info, RUN_SETUP },
 	{ "upload-archive", cmd_upload_archive, NO_PARSEOPT },