在编译RegexKitLite的时候，报错如下：
Undefined symbols for architecture i386:
"_uregex_open", referenced from:
_rkl_getCachedRegex in RegexKitLite.o
"_uregex_groupCount", referenced from:
_rkl_getCachedRegex in RegexKitLite.o
"_uregex_setText", referenced from:
_rkl_setCachedRegexToString in RegexKitLite.o
_rkl_clearCachedRegexSetTo in RegexKitLite.o
-[RKLBlockEnumerationHelper initWithRegex:options:string:range:error:]in RegexKitLite.o
"_uregex_start", referenced from:
_rkl_performRegexOp in RegexKitLite.o
_rkl_search in RegexKitLite.o
_rkl_findRanges in RegexKitLite.o
"_uregex_end", referenced from:
_rkl_performRegexOp in RegexKitLite.o
_rkl_search in RegexKitLite.o
_rkl_findRanges in RegexKitLite.o
"_uregex_find", referenced from:
_rkl_search in RegexKitLite.o
"_uregex_findNext", referenced from:
_rkl_search in RegexKitLite.o
_rkl_replaceAll in RegexKitLite.o
"_uregex_reset", referenced from:
_rkl_replaceAll in RegexKitLite.o
"_uregex_appendReplacement", referenced from:
_rkl_replaceAll in RegexKitLite.o
"_uregex_appendTail", referenced from:
_rkl_replaceAll in RegexKitLite.o
"_uregex_close", referenced from:
_rkl_clearCachedRegex in RegexKitLite.o
"_u_errorName", referenced from:
_rkl_userInfoDictionary in RegexKitLite.o
_rkl_makeNSError in RegexKitLite.o
_rkl_NSExceptionForRegex in RegexKitLite.o
"_u_strlen", referenced from:
_rkl_userInfoDictionary in RegexKitLite.o
"_uregex_clone", referenced from:
-[RKLBlockEnumerationHelper initWithRegex:options:string:range:error:]in RegexKitLite.o
ld: symbol(s) not found for architecture i386
collect2: ld returned 1 exit status
解决办法：
在项目的编译设置中找到Other Linker Flags，然后在后面字段空白处双击，添加“-licucore”就可以了。
原文：http://www.cnblogs.com/Cheetah-yang/p/4699534.html