Fix some usually disabled compiler warnings (#1286)

* Fixes from temporarily re-enabling more compiler warnings

* More edits suggested by cppcheck

* Fix hanging on append_yylval_string

* Fix FOR loop increment

src/asm/main.cpp

@@ -323,7 +323,7 @@ int main(int argc, char *argv[])
 			warnings = false;
 			break;
 
-			unsigned int maxValue;
+			unsigned long maxValue;
 		case 'X':
 			maxValue = strtoul(musl_optarg, &endptr, 0);