GYP fixes: -Werror, snapshot.log, want_separate_host_toolset detection

build/common.gypi

Index: build/common.gypi
diff --git a/build/common.gypi b/build/common.gypi
index 5a3da526a8a9e89479feab0e3846dad31b9d1f60..c41b2b2b626e95ed6a606d19b589615fae0957a0 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -32,25 +32,30 @@
     'visibility%': 'hidden',
     'msvs_multi_core_compile%': '1',
     'variables': {
-      'conditions': [
-        [ 'OS=="linux" or OS=="freebsd" or OS=="openbsd"', {
-          # This handles the Linux platforms we generally deal with. Anything
-          # else gets passed through, which probably won't work very well; such
-          # hosts should pass an explicit target_arch to gyp.
-          'host_arch%':
-            '<!(uname -m | sed -e "s/i.86/ia32/;s/x86_64/x64/;s/amd64/x64/;s/arm.*/arm/")',
-        }, {  # OS!="linux" and OS!="freebsd" and OS!="openbsd"
-          'host_arch%': 'ia32',
-        }],
-      ],
+      'variables': {
+        'conditions': [
+          [ 'OS=="linux" or OS=="freebsd" or OS=="openbsd"', {
+            # This handles the Linux platforms we generally deal with. Anything
+            # else gets passed through, which probably won't work very well; such
+            # hosts should pass an explicit target_arch to gyp.
+            'host_arch%':
+              '<!(uname -m | sed -e "s/i.86/ia32/;s/x86_64/x64/;s/amd64/x64/;s/arm.*/arm/")',
+          }, {  # OS!="linux" and OS!="freebsd" and OS!="openbsd"
+            'host_arch%': 'ia32',
+          }],
+        ],
+      },
+      'host_arch%': '<(host_arch)',
+      'target_arch%': '<(host_arch)',
+      'v8_target_arch%': '<(target_arch)',
     },
     'host_arch%': '<(host_arch)',
-    'target_arch%': '<(host_arch)',
-    'v8_target_arch%': '<(target_arch)',
+    'target_arch%': '<(target_arch)',
+    'v8_target_arch%': '<(v8_target_arch)',
     'v8_enable_debugger_support%': 1,
     'conditions': [
-      ['(target_arch=="arm" and host_arch!="arm") or \
-        (target_arch=="x64" and host_arch!="x64")', {
+      ['(v8_target_arch=="arm" and host_arch!="arm") or \
+        (v8_target_arch=="x64" and host_arch!="x64")', {
         'want_separate_host_toolset': 1,
       }, {
         'want_separate_host_toolset': 0,
@@ -80,8 +85,9 @@
   'conditions': [
     [ 'OS=="linux" or OS=="freebsd" or OS=="openbsd" or OS=="solaris"', {
       'target_defaults': {
-        'cflags': [ '-Wall', '-pthread', '-fno-rtti', '-fno-exceptions',
-                    '-pedantic' ],
+        'cflags': [ '-Wall', '-Werror', '-W', '-Wno-unused-parameter',
+                    '-Wnon-virtual-dtor', '-pthread', '-fno-rtti',
+                    '-fno-exceptions', '-pedantic' ],
         'ldflags': [ '-pthread', ],
         'conditions': [
           [ 'target_arch=="ia32"', {