Add cros_{target,host,v8_snapshot}_{nm,readelf} vars to GN build.

build/toolchain/cros/BUILD.gn

Index: build/toolchain/cros/BUILD.gn
diff --git a/build/toolchain/cros/BUILD.gn b/build/toolchain/cros/BUILD.gn
index 10bcca43eec9a0fb644b7556e3d6445031b0f9ca..3619828c820346967af168a78f35e2e3f18e0cf7 100644
--- a/build/toolchain/cros/BUILD.gn
+++ b/build/toolchain/cros/BUILD.gn
@@ -40,8 +40,11 @@ declare_args() {
   cros_target_cc = "gcc"
   cros_target_cxx = "g++"
   cros_target_ld = ""
+  cros_target_nm = ""
+  cros_target_readelf = ""
 
-  # These can be optionally set.
+  # These can be optionally set. The "_cppflags"  will be applied to *both*
+  # C and C++ files; use "_cxxflags" for C++-only flags.
   cros_target_extra_cflags = ""
   cros_target_extra_cppflags = ""
   cros_target_extra_cxxflags = ""
@@ -53,6 +56,8 @@ declare_args() {
   cros_host_cc = "gcc"
   cros_host_cxx = "g++"
   cros_host_ld = ""
+  cros_host_nm = ""
+  cros_host_readelf = ""
   cros_host_extra_cflags = ""
   cros_host_extra_cppflags = ""
   cros_host_extra_cxxflags = ""
@@ -63,6 +68,8 @@ declare_args() {
   cros_v8_snapshot_cc = "gcc"
   cros_v8_snapshot_cxx = "g++"
   cros_v8_snapshot_ld = ""
+  cros_v8_snapshot_nm = ""
+  cros_v8_snapshot_readelf = ""
   cros_v8_snapshot_extra_cflags = ""
   cros_v8_snapshot_extra_cppflags = ""
   cros_v8_snapshot_extra_cxxflags = ""
@@ -86,6 +93,12 @@ gcc_toolchain("target") {
   if (cros_target_ld != "") {
     ld = cros_target_ld
   }
+  if (cros_target_nm != "") {
+    nm = cros_target_nm
+  }
+  if (cros_target_readelf != "") {
+    readelf = cros_target_readelf
+  }
   extra_cflags = cros_target_extra_cflags
   extra_cppflags = cros_target_extra_cppflags
   extra_cxxflags = cros_target_extra_cxxflags
@@ -107,6 +120,12 @@ gcc_toolchain("host") {
   if (cros_host_ld != "") {
     ld = cros_host_ld
   }
+  if (cros_host_nm != "") {
+    nm = cros_host_nm
+  }
+  if (cros_host_readelf != "") {
+    readelf = cros_host_readelf
+  }
   extra_cflags = cros_host_extra_cflags
   extra_cppflags = cros_host_extra_cppflags
   extra_cxxflags = cros_host_extra_cxxflags
@@ -129,6 +148,12 @@ gcc_toolchain("v8_snapshot") {
   if (cros_v8_snapshot_ld != "") {
     ld = cros_v8_snapshot_ld
   }
+  if (cros_v8_snapshot_nm != "") {
+    nm = cros_v8_snapshot_nm
+  }
+  if (cros_v8_snapshot_readelf != "") {
+    readelf = cros_v8_snapshot_readelf
+  }
   extra_cflags = cros_v8_snapshot_extra_cflags
   extra_cppflags = cros_v8_snapshot_extra_cppflags
   extra_cxxflags = cros_v8_snapshot_extra_cxxflags