Building Boost 1.70.0 with icu 64.2 - c++

Question

I have built icu 64.2 (debug and release for both x86 and x64). My build passes all the tests, so I know icu is not the issue.
I have also built a 64-bit version of boost 1.70.0 using the following b2 build command:
b2 address-model=64 -sICU_PATH=C:\icu-release-64-2\icu4c threading=multi --build-type=complete --toolset=msvc-14.1 -j 6
b2 is detecting my icu build and is showing:
- has_icu builds : yes
When I try to build my project with this boost/regex/icu code:
bool is_valid_password(const icu::UnicodeString& password, const icu::UnicodeString& requirements)
{
return boost::u32regex_match(password, boost::make_u32regex(requirements));
}
I get the following error:
1>------ Build started: Project: URLParser, Configuration: Debug x64 ------
1>URLParser.obj : error LNK2019: unresolved external symbol u_tolower_64 referenced in function "public: int __cdecl boost::icu_regex_traits::translate_nocase(int)const " (?translate_nocase#icu_regex_traits#boost##QEBAHH#Z)
1>libboost_regex-vc141-mt-gd-x64-1_70.lib(icu.obj) : error LNK2001: unresolved external symbol u_tolower_64
1>URLParser.obj : error LNK2019: unresolved external symbol "__declspec(dllimport) public: int __cdecl icu_64::UnicodeString::length(void)const " (__imp_?length#UnicodeString#icu_64##QEBAHXZ) referenced in function "class boost::basic_regex<int,class boost::icu_regex_traits> __cdecl boost::make_u32regex(class icu_64::UnicodeString const &,unsigned int)" (?make_u32regex#boost##YA?AV?$basic_regex#HVicu_regex_traits#boost###1#AEBVUnicodeString#icu_64##I#Z)
1>URLParser.obj : error LNK2019: unresolved external symbol "__declspec(dllimport) public: char16_t const * __cdecl icu_64::UnicodeString::getBuffer(void)const " (__imp_?getBuffer#UnicodeString#icu_64##QEBAPEB_SXZ) referenced in function "class boost::basic_regex<int,class boost::icu_regex_traits> __cdecl boost::make_u32regex(class icu_64::UnicodeString const &,unsigned int)" (?make_u32regex#boost##YA?AV?$basic_regex#HVicu_regex_traits#boost###1#AEBVUnicodeString#icu_64##I#Z)
1>libboost_regex-vc141-mt-gd-x64-1_70.lib(icu.obj) : error LNK2019: unresolved external symbol u_isblank_64 referenced in function "public: bool __cdecl boost::icu_regex_traits::isctype(int,unsigned __int64)const " (?isctype#icu_regex_traits#boost##QEBA_NH_K#Z)
1>libboost_regex-vc141-mt-gd-x64-1_70.lib(icu.obj) : error LNK2019: unresolved external symbol u_isspace_64 referenced in function "public: unsigned __int64 __cdecl boost::icu_regex_traits::lookup_classname(int const *,int const *)const " (?lookup_classname#icu_regex_traits#boost##QEBA_KPEBH0#Z)
1>libboost_regex-vc141-mt-gd-x64-1_70.lib(icu.obj) : error LNK2019: unresolved external symbol u_charType_64 referenced in function "public: bool __cdecl boost::icu_regex_traits::isctype(int,unsigned __int64)const " (?isctype#icu_regex_traits#boost##QEBA_NH_K#Z)
1>libboost_regex-vc141-mt-gd-x64-1_70.lib(icu.obj) : error LNK2019: unresolved external symbol u_charFromName_64 referenced in function "public: class std::vector<int,class std::allocator<int> > __cdecl boost::icu_regex_traits::lookup_collatename(int const *,int const *)const " (?lookup_collatename#icu_regex_traits#boost##QEBA?AV?$vector#HV?$allocator#H#std###std##PEBH0#Z)
1>libboost_regex-vc141-mt-gd-x64-1_70.lib(icu.obj) : error LNK2019: unresolved external symbol u_digit_64 referenced in function "public: bool __cdecl boost::icu_regex_traits::isctype(int,unsigned __int64)const " (?isctype#icu_regex_traits#boost##QEBA_NH_K#Z)
1>libboost_regex-vc141-mt-gd-x64-1_70.lib(icu.obj) : error LNK2019: unresolved external symbol "__declspec(dllimport) public: __cdecl icu_64::Locale::Locale(void)" (__imp_??0Locale#icu_64##QEAA#XZ) referenced in function "public: __cdecl boost::icu_regex_traits::icu_regex_traits(void)" (??0icu_regex_traits#boost##QEAA#XZ)
1>libboost_regex-vc141-mt-gd-x64-1_70.lib(icu.obj) : error LNK2019: unresolved external symbol "__declspec(dllimport) public: __cdecl icu_64::Locale::Locale(class icu_64::Locale const &)" (__imp_??0Locale#icu_64##QEAA#AEBV01##Z) referenced in function "public: __cdecl boost::re_detail_107000::icu_regex_traits_implementation::icu_regex_traits_implementation(class icu_64::Locale const &)" (??0icu_regex_traits_implementation#re_detail_107000#boost##QEAA#AEBVLocale#icu_64###Z)
1>libboost_regex-vc141-mt-gd-x64-1_70.lib(icu.obj) : error LNK2019: unresolved external symbol "__declspec(dllimport) public: __cdecl icu_64::Locale::Locale(class icu_64::Locale &&)" (__imp_??0Locale#icu_64##QEAA#$$QEAV01##Z) referenced in function "public: class icu_64::Locale __cdecl boost::basic_regex<int,class boost::icu_regex_traits>::getloc(void)const " (?getloc#?$basic_regex#HVicu_regex_traits#boost###boost##QEBA?AVLocale#icu_64##XZ)
1>libboost_regex-vc141-mt-gd-x64-1_70.lib(icu.obj) : error LNK2019: unresolved external symbol "__declspec(dllimport) public: virtual __cdecl icu_64::Locale::~Locale(void)" (__imp_??1Locale#icu_64##UEAA#XZ) referenced in function "public: __cdecl boost::icu_regex_traits::icu_regex_traits(void)" (??0icu_regex_traits#boost##QEAA#XZ)
1>libboost_regex-vc141-mt-gd-x64-1_70.lib(icu.obj) : error LNK2019: unresolved external symbol "__declspec(dllimport) public: static class icu_64::Collator * __cdecl icu_64::Collator::createInstance(class icu_64::Locale const &,enum UErrorCode &)" (__imp_?createInstance#Collator#icu_64##SAPEAV12#AEBVLocale#2#AEAW4UErrorCode###Z) referenced in function "public: __cdecl boost::re_detail_107000::icu_regex_traits_implementation::icu_regex_traits_implementation(class icu_64::Locale const &)" (??0icu_regex_traits_implementation#re_detail_107000#boost##QEAA#AEBVLocale#icu_64###Z)
1>C:\Users\nicho\source\repos\URLParser\x64\Debug\URLParser.exe : fatal error LNK1120: 13 unresolved externals
1>Done building project "URLParser.vcxproj" -- FAILED.
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========
I should also note that I built icu and boost with the same compiler and MSVC toolset. Any ideas why boost wouldn't be linking to icu?