Follow up to 6748ff7

* Fixed pre-increment and pre-decrement operators for achievement condition parsing.
Thanks to @Lemongrass3110!

src/map/achievement.c

@@ -879,8 +879,8 @@ const char* av_parse_subexpr(const char* p, int limit, struct av_condition *pare
 	p = skip_space(p);
 
 	while((
-			(op=C_ADD,opl=9,len=1,*p=='+') ||
-			(op=C_SUB,opl=9,len=1,*p=='-') ||
+			((op=C_ADD,opl=9,len=1,*p=='+') && p[1]!='+') ||
+			((op=C_SUB,opl=9,len=1,*p=='-') && p[1]!='-') ||
 			(op=C_MUL,opl=10,len=1,*p=='*') ||
 			(op=C_DIV,opl=10,len=1,*p=='/') ||
 			(op=C_MOD,opl=10,len=1,*p=='%') ||