Fix some of the issues from #478 (Warnings in Visual Studio build with -W4)

http://sourceforge.net/apps/trac/cppcheck/ticket/478

src/checkmemoryleak.cpp

@@ -945,9 +945,8 @@ Token *CheckMemoryLeakInFunction::getcode(const Token *tok, std::list<const Toke
         }
 
         // Callback..
-        bool matchFirst;
-        if ((matchFirst = Token::Match(tok, "( %var%")) ||
-            Token::Match(tok, "( * %var%"))
+        bool matchFirst = Token::Match(tok, "( %var%");
+        if (matchFirst || Token::Match(tok, "( * %var%"))
         {
             int tokIdx = matchFirst ? 2 : 3;
 

src/errorlogger.cpp

@@ -67,7 +67,7 @@ bool ErrorLogger::ErrorMessage::deserialize(const std::string &data)
         std::string temp;
         for (unsigned int i = 0; i < len && iss.good(); ++i)
         {
-            char c = iss.get();
+            char c = static_cast<char>(iss.get());
             temp.append(1, c);
         }
 
@@ -94,7 +94,7 @@ bool ErrorLogger::ErrorMessage::deserialize(const std::string &data)
         std::string temp;
         for (unsigned int i = 0; i < len && iss.good(); ++i)
         {
-            char c = iss.get();
+            char c = static_cast<char>(iss.get());
             temp.append(1, c);
         }
 

src/preprocessor.cpp

@@ -286,7 +286,7 @@ std::string Preprocessor::read(std::istream &istr)
         if (ch == '\\')
         {
             char chNext = 0;
-            while (true)
+            for (;;)
             {
                 chNext = (char)istr.peek();
                 if (chNext != '\n' && chNext != '\r' && (chNext > 0) &&