Display more accurate help information

use commond 'gn help  target_cpu'

Change-Id: Iea2b94544787e6517c7442948cc13aab022bcd5c
Reviewed-on: https://gn-review.googlesource.com/c/gn/+/12600
Reviewed-by: Brett Wilson <brettw@chromium.org>
Commit-Queue: Brett Wilson <brettw@chromium.org>

AUTHORS

diff --git a/AUTHORS b/AUTHORS
index 622d117..0c64ad6 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -32,6 +32,7 @@
 Julien Brianceau <jbriance@cisco.com>
 Kal Conley <kcconley@gmail.com>
 Kamil Rytarowski <krytarowski@gmail.com>
+Ma Aiguo <maaiguo@uniontech.com>
 Martijn Croonen <martijn@martijnc.be>
 Matej Knopp <matej.knopp@gmail.com>
 Michael Gilbert <floppymaster@gmail.com>
@@ -48,4 +49,3 @@
 Yuriy Taraday <yorik.sar@gmail.com>
 Oleksandr Motsok <boramaabak@gmail.com>
 Ihor Karavan <ihorkaravan96@gmail.com>
-Ma Aiguo <maaiguo@uniontech.com>

src/gn/variables.cc

diff --git a/src/gn/variables.cc b/src/gn/variables.cc
index 433d280..fba20e0 100644
--- a/src/gn/variables.cc
+++ b/src/gn/variables.cc
@@ -124,6 +124,13 @@
   - "arm"
   - "arm64"
   - "mipsel"
+  - "mips64el"
+  - "s390x"
+  - "ppc64"
+  - "riscv32"
+  - "riscv64"
+  - "e2k"
+  - "loong64"
 )";
 
 const char kTargetName[] = "target_name";