alwaysTrueFalse: Dont write warning when comparison is made in macro

lib/checkcondition.cpp

@@ -977,6 +977,8 @@ void CheckCondition::alwaysTrueFalse()
                 continue;
             if (!tok->values.front().isKnown())
                 continue;
+            if (tok->isExpandedMacro())
+                continue;
 
             if (tok->astParent() && Token::Match(tok->astParent()->previous(), "%name% ("))
                 alwaysTrueFalseError(tok, tok->values.front().intvalue != 0);

test/testcondition.cpp

@@ -1510,6 +1510,14 @@ private:
               "  if (!x) {}\n"
               "}");
         ASSERT_EQUALS("[test.cpp:4]: (style) Condition !x is always true\n", errout.str());
+
+        // Avoid FP when condition comes from macro
+        check("void f() {\n"
+              "  int x = 0;\n"
+              "  if (a) { return; }\n" // <- this is just here to fool simplifyKnownVariabels
+              "  if ($!x) {}\n"
+              "}");
+        ASSERT_EQUALS("", errout.str());
     }
 };