clang-tidy: Silence use-equals-default warning

clang-tidy 7 has an option to suppress this warning in macros which
defaults to '1'.  Set the option to '0' and silence the warning
explicitly.
diff --git a/.clang-tidy b/.clang-tidy
index dace6f1..a41ab64 100644
--- a/.clang-tidy
+++ b/.clang-tidy
@@ -34,4 +34,6 @@
 CheckOptions:
   - key:   modernize-use-default-member-init.UseAssignment
     value: '1'
+  - key:   modernize-use-equals-default.IgnoreMacros
+    value: '0'
 ...
diff --git a/Source/cmGeneratorExpressionNode.cxx b/Source/cmGeneratorExpressionNode.cxx
index eb66ed5..aac188e 100644
--- a/Source/cmGeneratorExpressionNode.cxx
+++ b/Source/cmGeneratorExpressionNode.cxx
@@ -95,7 +95,7 @@
 #define BOOLEAN_OP_NODE(OPNAME, OP, SUCCESS_VALUE, FAILURE_VALUE)             \
   static const struct OP##Node : public cmGeneratorExpressionNode             \
   {                                                                           \
-    OP##Node() {}                                                             \
+    OP##Node() {} /* NOLINT(modernize-use-equals-default) */                  \
     virtual int NumExpectedParameters() const { return OneOrMoreParameters; } \
                                                                               \
     std::string Evaluate(const std::vector<std::string>& parameters,          \