msvs/ninja win: Fix support for ImageHasSafeExceptionHandlers

test/win/linker-flags/safeseh.gyp

Index: test/win/linker-flags/safeseh.gyp
diff --git a/test/win/linker-flags/safeseh.gyp b/test/win/linker-flags/safeseh.gyp
index 61036200519e332cdf9a9ad296d5465f2bc177a5..c4ed068805dffefa7b98d45fca32d857ecbfaf7d 100644
--- a/test/win/linker-flags/safeseh.gyp
+++ b/test/win/linker-flags/safeseh.gyp
@@ -8,6 +8,12 @@
       'target_name': 'test_safeseh_default',
       'type': 'executable',
       'msvs_settings': {
+        # By default, msvs passes /SAFESEH for Link, but not for MASM.  In
+        # order for test_safeseh_default to link successfully, we need to
+        # explicitly specify /SAFESEH for MASM.
+        'MASM': {
+          'UseSafeExceptionHandlers': 'true',
+        },
       },
       'sources': [
         'safeseh_hello.cc',