Split up builtin commands into separate files from git.c

Right now it split it into "builtin-log.c" for log-related commands
("log", "show" and "whatchanged"), and "builtin-help.c" for the
informational commands (usage printing and "help" and "version").

This just makes things easier to read, I find.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
diff --git a/builtin.h b/builtin.h
new file mode 100644
index 0000000..47408a0
--- /dev/null
+++ b/builtin.h
@@ -0,0 +1,23 @@
+#ifndef BUILTIN_H
+#define BUILTIN_H
+
+#ifndef PATH_MAX
+# define PATH_MAX 4096
+#endif
+
+extern const char git_version_string[];
+
+void cmd_usage(int show_all, const char *exec_path, const char *fmt, ...)
+#ifdef __GNUC__
+	__attribute__((__format__(__printf__, 3, 4), __noreturn__))
+#endif
+	;
+
+extern int cmd_help(int argc, const char **argv, char **envp);
+extern int cmd_version(int argc, const char **argv, char **envp);
+
+extern int cmd_whatchanged(int argc, const char **argv, char **envp);
+extern int cmd_show(int argc, const char **argv, char **envp);
+extern int cmd_log(int argc, const char **argv, char **envp);
+
+#endif