Copy dbgcore.dll to the build directory.

build/vs_toolchain.py

Index: build/vs_toolchain.py
diff --git a/build/vs_toolchain.py b/build/vs_toolchain.py
index 2f1ef1735752a526f959a02690fa18fd1e0e8fcf..e131a0db2b428084884a72ac7caaca4ddb378a1d 100755
--- a/build/vs_toolchain.py
+++ b/build/vs_toolchain.py
@@ -311,7 +311,7 @@ def CopyDlls(target_dir, configuration, target_cpu):
 
 
 def _CopyDebugger(target_dir, target_cpu):
-  """Copy dbghelp.dll into the requested directory as needed.
+  """Copy dbghelp.dll and dbgcore.dll into the requested directory as needed.
 
   target_cpu is one of 'x86' or 'x64'.
 
@@ -319,19 +319,23 @@ def _CopyDebugger(target_dir, target_cpu):
   from the SDK directory avoids using the system copy of dbghelp.dll which then
   ensures compatibility with recent debug information formats, such as VS
   2017 /debug:fastlink PDBs.
+
+  dbgcore.dll is needed when using some functions from dbghelp.dll (like
+  MinidumpWriteDump).
   """
   win_sdk_dir = SetEnvironmentAndGetSDKDir()
   if not win_sdk_dir:
     return
 
-  debug_file = 'dbghelp.dll'
-  full_path = os.path.join(win_sdk_dir, 'Debuggers', target_cpu, debug_file)
-  if not os.path.exists(full_path):
-    raise Exception('dbghelp.dll not found in "%s"\r\nYou must install the '
-                    '"Debugging Tools for Windows" feature from the Windows '
-                    '10 SDK.' % full_path)
-  target_path = os.path.join(target_dir, debug_file)
-  _CopyRuntimeImpl(target_path, full_path)
+  debug_files = ['dbghelp.dll', 'dbgcore.dll']
+  for debug_file in debug_files:
+    full_path = os.path.join(win_sdk_dir, 'Debuggers', target_cpu, debug_file)
+    if not os.path.exists(full_path):
+      raise Exception('%s not found in "%s"\r\nYou must install the '
+                      '"Debugging Tools for Windows" feature from the Windows '
+                      '10 SDK.' % (debug_file, full_path))
+    target_path = os.path.join(target_dir, debug_file)
+    _CopyRuntimeImpl(target_path, full_path)
 
 
 def _GetDesiredVsToolchainHashes():