Fixed #4171 (don't choke when parentheses are missing from macros)

lib/tokenize.cpp

@@ -1598,8 +1598,22 @@ bool Tokenizer::tokenize(std::istream &code,
                 // 'for each ( )' -> 'for ( )'
                 tok->deleteNext();
             else {
-                syntaxError(tok);
-                return false;
+                // locate the ')' parenthesis (the Token::link is not set yet)
+                // Then replace 'if MACRO(X)' with 'if (MACRO(X))'
+                unsigned int parlevel = 0;
+                for (Token *tok2 = tok; tok2; tok2 = tok2->next()) {
+                    if (tok2->str() == "(")
+                        ++parlevel;
+                    else if (tok2->str() == ")") {
+                        if (parlevel == 1) {
+                            tok->insertToken("(");
+                            tok2->insertToken(")");
+                        }
+                        if (parlevel <= 1)
+                            break;
+                        --parlevel;
+                    }
+                }
             }
         }
     }

test/testtokenize.cpp

@@ -696,10 +696,10 @@ private:
     }
 
     void wrong_syntax_if_macro() {
-        // #2518
-        const std::string code("void f() { if MACRO(); }");
-        tokenizeAndStringify(code.c_str(), false);
-        ASSERT_EQUALS("[test.cpp:1]: (error) syntax error\n", errout.str());
+        // #2518 and #4171
+        const char code[] = "void f() { if MACRO() { } }";
+        ASSERT_EQUALS("void f ( ) { if ( MACRO ( ) ) { } }", tokenizeAndStringify(code, false));
+        ASSERT_EQUALS("", errout.str());
     }
 
     void foreach() {