ios - il2cpp compilation errors with Unity3d -

i trying compile unity3d c# scripts run on arm64 devices ios.

the unity build generates xcode project no problems xcode build produces semantic issue errors:

compilec /users/luis/library/developer/xcode/deriveddata/unity-iphone-eqdiboubmtwcvkcuyaficuwofpvl/build/intermediates/unity-iphone.build/debug-iphoneos/unity-iphone.build/objects-normal/armv7/assemblyattributes_g_mono_posix_assembly.o classes/native/assemblyattributes_g_mono_posix_assembly.cpp normal armv7 c++ com.apple.compilers.llvm.clang.1_0.compiler     cd /users/luis/projects/unity/myproject-unity/unity/myproject_xcode     export lang=en_us.us-ascii     export path="/applications/xcode.app/contents/developer/platforms/iphoneos.platform/developer/usr/bin:/applications/xcode.app/contents/developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin"     /applications/xcode.app/contents/developer/toolchains/xcodedefault.xctoolchain/usr/bin/clang -x c++ -arch armv7 -fmessage-length=0 -fdiagnostics-show-note-include-stack -fmacro-backtrace-limit=0 -std=c++11 -stdlib=libc++ -wno-trigraphs -fno-rtti -fpascal-strings -o0 -wno-missing-field-initializers -wno-missing-prototypes -wno-non-virtual-dtor -wno-overloaded-virtual -wno-exit-time-destructors -wno-missing-braces -wparentheses -wswitch -wno-unused-function -wno-unused-label -wno-unused-parameter -wunused-variable -wunused-value -wno-empty-body -wno-uninitialized -wno-unknown-pragmas -wno-shadow -wno-four-char-constants -wno-conversion -wno-constant-conversion -wno-int-conversion -wno-bool-conversion -wno-enum-conversion -wno-shorten-64-to-32 -wno-newline-eof -wno-c++11-extensions -isysroot /applications/xcode.app/contents/developer/platforms/iphoneos.platform/developer/sdks/iphoneos8.3.sdk -fstrict-aliasing -wdeprecated-declarations -winvalid-offsetof -g -fvisibility=hidden -fvisibility-inlines-hidden -wno-sign-conversion -miphoneos-version-min=8.1 -iquote /users/luis/library/developer/xcode/deriveddata/unity-iphone-eqdiboubmtwcvkcuyaficuwofpvl/build/intermediates/unity-iphone.build/debug-iphoneos/unity-iphone.build/myproject-generated-files.hmap -i/users/luis/library/developer/xcode/deriveddata/unity-iphone-eqdiboubmtwcvkcuyaficuwofpvl/build/intermediates/unity-iphone.build/debug-iphoneos/unity-iphone.build/myproject-own-target-headers.hmap -i/users/luis/library/developer/xcode/deriveddata/unity-iphone-eqdiboubmtwcvkcuyaficuwofpvl/build/intermediates/unity-iphone.build/debug-iphoneos/unity-iphone.build/myproject-all-target-headers.hmap -iquote /users/luis/library/developer/xcode/deriveddata/unity-iphone-eqdiboubmtwcvkcuyaficuwofpvl/build/intermediates/unity-iphone.build/debug-iphoneos/unity-iphone.build/myproject-project-headers.hmap -i/users/luis/library/developer/xcode/deriveddata/unity-iphone-eqdiboubmtwcvkcuyaficuwofpvl/build/products/debug-iphoneos/include -i/users/luis/projects/unity/myproject-unity/unity/myproject_xcode/classes -i/users/luis/projects/unity/myproject-unity/unity/myproject_xcode -i/users/luis/projects/unity/myproject-unity/unity/myproject_xcode/classes/native -i/users/luis/projects/unity/myproject-unity/unity/myproject_xcode/libraries/bdwgc/include -i/users/luis/projects/unity/myproject-unity/unity/myproject_xcode/libraries/libil2cpp/include -i/users/luis/library/developer/xcode/deriveddata/unity-iphone-eqdiboubmtwcvkcuyaficuwofpvl/build/intermediates/unity-iphone.build/debug-iphoneos/unity-iphone.build/derivedsources/armv7 -i/users/luis/library/developer/xcode/deriveddata/unity-iphone-eqdiboubmtwcvkcuyaficuwofpvl/build/intermediates/unity-iphone.build/debug-iphoneos/unity-iphone.build/derivedsources -f/users/luis/library/developer/xcode/deriveddata/unity-iphone-eqdiboubmtwcvkcuyaficuwofpvl/build/products/debug-iphoneos -f/users/luis/projects/unity/myproject-unity/unity/myproject_xcode/../assets/plugins/myproject-ios/.libs -mno-thumb -dinit_scripting_backend=1 -include /users/luis/library/developer/xcode/deriveddata/unity-iphone-eqdiboubmtwcvkcuyaficuwofpvl/build/intermediates/precompiledheaders/prefix-ezhqqfjflyedusduqsaicoevmmnd/prefix.pch -mmd -mt dependencies -mf /users/luis/library/developer/xcode/deriveddata/unity-iphone-eqdiboubmtwcvkcuyaficuwofpvl/build/intermediates/unity-iphone.build/debug-iphoneos/unity-iphone.build/objects-normal/armv7/assemblyattributes_g_mono_posix_assembly.d --serialize-diagnostics /users/luis/library/developer/xcode/deriveddata/unity-iphone-eqdiboubmtwcvkcuyaficuwofpvl/build/intermediates/unity-iphone.build/debug-iphoneos/unity-iphone.build/objects-normal/armv7/assemblyattributes_g_mono_posix_assembly.dia -c /users/luis/projects/unity/myproject-unity/unity/myproject_xcode/classes/native/assemblyattributes_g_mono_posix_assembly.cpp -o /users/luis/library/developer/xcode/deriveddata/unity-iphone-eqdiboubmtwcvkcuyaficuwofpvl/build/intermediates/unity-iphone.build/debug-iphoneos/unity-iphone.build/objects-normal/armv7/assemblyattributes_g_mono_posix_assembly.o  /users/luis/projects/unity/myproject-unity/unity/myproject_xcode/classes/native/assemblyattributes_g_mono_posix_assembly.cpp:51:3: error: unknown type name 'assemblytitleattribute_t500'; did mean 'assemblytitleattribute_t499'?                 assemblytitleattribute_t500 * tmp;                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~                 assemblytitleattribute_t499 in file included /users/luis/projects/unity/myproject-unity/unity/myproject_xcode/classes/native/assemblyattributes_g_mono_posix_assembly.cpp:8: /users/luis/projects/unity/myproject-unity/unity/myproject_xcode/classes/native/mscorlib_system_reflection_assemblytitleattributemethoddeclarations.h:8:8: note: 'assemblytitleattribute_t499' declared here struct assemblytitleattribute_t499;        ^ /users/luis/projects/unity/myproject-unity/unity/myproject_xcode/classes/native/assemblyattributes_g_mono_posix_assembly.cpp:52:10: error: unknown type name 'assemblytitleattribute_t500'; did mean 'assemblytitleattribute_t499'?                 tmp = (assemblytitleattribute_t500 *)il2cpp_codegen_object_new (&assemblytitleattribute_t500_il2cpp_typeinfo);                        ^~~~~~~~~~~~~~~~~~~~~~~~~~~                        assemblytitleattribute_t499 .....                 ^ fatal error: many errors emitted, stopping [-ferror-limit=] 20 errors generated. 

it happened when started using micro msclib , using link.xml file suggested here (http://docs.unity3d.com/manual/iphone-playersizeoptimization.html) did not help. also, don't know have put in link.xml file in case.

edit: found out happens because set compatibility level .net 2.0 subset. still don't know classes using cause error.