Pass the /safeseh option to ml.exe.

pylib/gyp/msvs_emulation.py

Index: pylib/gyp/msvs_emulation.py
diff --git a/pylib/gyp/msvs_emulation.py b/pylib/gyp/msvs_emulation.py
index 6b5dfc2180f474a48723437e3b57a448e6104eab..a587d79dc795fa5d244eb86889c83af29aa4042c 100644
--- a/pylib/gyp/msvs_emulation.py
+++ b/pylib/gyp/msvs_emulation.py
@@ -345,6 +345,15 @@ class MsvsSettings(object):
     else:
       return None
 
+  def GetAsmflags(self, config):
+    """Returns the flags that need to be added to ml invocations."""
+    config = self._TargetConfig(config)
+    asmflags = []
+    safeseh = self._Setting(('MASM', 'UseSafeExceptionHandlers'), config)
+    if safeseh == 'true':
+      asmflags.append('/safeseh')
+    return asmflags
+
   def GetCflags(self, config):
     """Returns the flags that need to be added to .c and .cc compilations."""
     config = self._TargetConfig(config)