Arch detection: select ppc64 arch on os400 operating system.

Change-Id: Ib2ca3cb38f1a6ba3378eb0dab24baf2b8c3f79b6
Reviewed-on: https://gn-review.googlesource.com/c/gn/+/10640
Reviewed-by: Brett Wilson <brettw@chromium.org>
Commit-Queue: Brett Wilson <brettw@chromium.org>

src/util/sys_info.cc

diff --git a/src/util/sys_info.cc b/src/util/sys_info.cc
index 082d2d6..8124e07 100644
--- a/src/util/sys_info.cc
+++ b/src/util/sys_info.cc
@@ -24,6 +24,7 @@
     return std::string();
   }
   std::string arch(info.machine);
+  std::string os(info.sysname);
   if (arch == "i386" || arch == "i486" || arch == "i586" || arch == "i686") {
     arch = "x86";
   } else if (arch == "i86pc") {
@@ -33,7 +34,7 @@
     arch = "x86_64";
   } else if (arch == "amd64") {
     arch = "x86_64";
-  } else if (std::string(info.sysname) == "AIX") {
+  } else if (os == "AIX" || os == "OS400") {
     arch = "ppc64";
   }
   return arch;