build: set v8_enable_verify_write_barriers for debug builds

It otherwise doesn't build.

Author: joyeecheung

configure.py

@@ -1876,6 +1876,7 @@ def configure_v8(o, configs):
   if sys.platform != 'darwin':
     if o['variables']['v8_enable_webassembly'] and o['variables']['target_arch'] == 'x64':
       o['variables']['v8_enable_wasm_simd256_revec'] = 1
+  o['variables']['v8_enable_verify_write_barriers'] = 1 if options.debug else 0
 
 def configure_openssl(o):
   variables = o['variables']

tools/v8_gypfiles/features.gypi

@@ -153,6 +153,10 @@
     # Use pre-generated static root pointer values from static-roots.h.
     'v8_enable_static_roots%': 0,
 
+    # Disable write barriers when GCs are non-incremental and
+    # heap has single generation.
+    'v8_enable_verify_write_barriers%': 0,
+
     # Enable code-generation-time checking of types in the CodeStubAssembler.
     'v8_enable_verify_csa%': 0,
 
@@ -430,6 +434,9 @@
       ['v8_enable_single_generation==1', {
         'defines': ['V8_ENABLE_SINGLE_GENERATION',],
       }],
+      ['v8_enable_verify_write_barriers==1', {
+        'defines': ['V8_VERIFY_WRITE_BARRIERS',],
+      }],
       ['v8_disable_write_barriers==1', {
         'defines': ['V8_DISABLE_WRITE_BARRIERS',],
       }],