S390: Makefile + Build Toolchain Updates

BUILD.gn

Index: BUILD.gn
diff --git a/BUILD.gn b/BUILD.gn
index c6bb4b522ac16d3925b018aee2a94bb86c1472ba..88097133c43099a7bca8e35af64327ed60d69a6c 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -171,12 +171,22 @@ config("toolchain") {
   if (v8_target_arch == "mips64el") {
     defines += [ "V8_TARGET_ARCH_MIPS64" ]
   }
+  if (v8_target_arch == "s390") {
+    defines += [ "V8_TARGET_ARCH_S390" ]
+  } 
+  if (v8_target_arch == "s390x") {
+    defines += [
+      "V8_TARGET_ARCH_S390",
+      "V8_TARGET_ARCH_S390X",
+    ]
+  }
   if (v8_target_arch == "x86") {
     defines += [ "V8_TARGET_ARCH_IA32" ]
   }
   if (v8_target_arch == "x64") {
     defines += [ "V8_TARGET_ARCH_X64" ]
   }
+     
   if (is_win) {
     defines += [ "WIN32" ]
     # TODO(jochen): Support v8_enable_prof.