Avoid an undefined-behaviour warning with -fsanitize=undefined.

Author: Clownacy

semantic.c

@@ -507,12 +507,13 @@ static cc_bool FindMacroParameter(const char* const remaining_line, const char*
 	for (;;)
 	{
 		other_parameter_position = strstr(other_parameter_end, identifier);
-		other_parameter_end = other_parameter_position + strlen(identifier);
 
 		/* Obviously bail if the identifier wasn't found. */
 		if (other_parameter_position == NULL)
 			break;
 
+		other_parameter_end = other_parameter_position + strlen(identifier);
+
 		/* If the identifier was in the middle of a larger block of letters/numbers, then don't replace it. */
 		/* (This is what AS does, and the Sonic 1 disassembly relies on this). */
 		if ((other_parameter_position == remaining_line || !IsMacroBlockingCharacter(other_parameter_position[-1])) && !IsMacroBlockingCharacter(other_parameter_end[0]))