loplugin:commaoperator: Ignore occurrence in FD_SET expansion on Windows

Change-Id: I66974c273918d6d887364e7d552e3caf63e16343

compilerplugins/clang/commaoperator.cxx

@@ -39,6 +39,21 @@ bool CommaOperator::VisitBinaryOperator(const BinaryOperator* binaryOp)
     if (ignoreLocation(binaryOp)) {
         return true;
     }
+    // Ignore FD_SET expanding to "...} while(0, 0)" in some Microsoft
+    // winsock2.h (TODO: improve heuristic of determining that the whole
+    // binaryOp is part of a single macro body expansion):
+    if (compiler.getSourceManager().isMacroBodyExpansion(
+            binaryOp->getLocStart())
+        && compiler.getSourceManager().isMacroBodyExpansion(
+            binaryOp->getOperatorLoc())
+        && compiler.getSourceManager().isMacroBodyExpansion(
+            binaryOp->getLocEnd())
+        && ignoreLocation(
+            compiler.getSourceManager().getSpellingLoc(
+                binaryOp->getOperatorLoc())))
+    {
+        return true;
+    }
     if (binaryOp->getOpcode() != BO_Comma) {
         return true;
     }