Roll GN: gn format is --in-place by default

gn/BUILD.gn

Index: gn/BUILD.gn
diff --git a/gn/BUILD.gn b/gn/BUILD.gn
index 48bd90f639ec7fcec227c2327180f787edf56f1f..1f7bd82bf2cf15cd8762c2b2bd501407b5911251 100644
--- a/gn/BUILD.gn
+++ b/gn/BUILD.gn
@@ -54,6 +54,10 @@ config("executable") {
   }
 }
 
+pool("link_pool") {
+  depth = 0  #unlimited
+}
+
 toolchain("gcc_like") {
   lib_switch = "-l"
   lib_dir_switch = "-L"
@@ -113,6 +117,7 @@ toolchain("gcc_like") {
     output_prefix = "lib"
     default_output_extension = ".so"
     description = "$cxx -shared ... -o {{output}}"
+    pool = ":link_pool"
   }
 
   tool("link") {
@@ -121,6 +126,7 @@ toolchain("gcc_like") {
       "{{root_out_dir}}/{{target_output_name}}{{output_extension}}",
     ]
     description = "$cxx ... -o {{output}}"
+    pool = ":link_pool"
   }
 
   tool("stamp") {