build fail in ubuntu 18.04

[elife33]

Consolidate compiler generated dependencies of target pam_akm [ 43%] Built target pam_akm [ 43%] Building C object src/external/openpam/pam_modules/CMakeFiles/pam_localauthentication.dir/modules/pam_localauthentication/pam_localauthentication.c.o /home/elife/sw/darling/src/external/openpam/pam_modules/modules/pam_localauthentication/pam_localauthentication.c:96:15: warning: implicit declaration of function 'LACreateNewContextWithACMContext' is invalid in C99 [-Wimplicit-function-declaration] context = LACreateNewContextWithACMContext(*externalized_context, &error); ^ /home/elife/sw/darling/src/external/openpam/pam_modules/modules/pam_localauthentication/pam_localauthentication.c:96:13: warning: incompatible integer to pointer conversion assigning to 'CFTypeRef' (aka 'const void *') from 'int' [-Wint-conversion] context = LACreateNewContextWithACMContext(*externalized_context, &error); ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ /home/elife/sw/darling/src/external/openpam/pam_modules/modules/pam_localauthentication/pam_localauthentication.c:115:10: warning: implicit declaration of function 'LAEvaluatePolicy' is invalid in C99 [-Wimplicit-function-declaration] if (!LAEvaluatePolicy(context, policy, options, &error)) { ^ /home/elife/sw/darling/src/external/openpam/pam_modules/modules/pam_localauthentication/pam_localauthentication.c:122:33: warning: implicit declaration of function 'LAVerifySEP' is invalid in C99 [-Wimplicit-function-declaration] if (!isContinuityUnlock && !LAVerifySEP(pwd->pw_uid, &error)) { ^ 4 warnings generated. /home/elife/sw/darling/src/external/openpam/pam_modules/modules/pam_localauthentication/pam_localauthentication.c:96:15: warning: implicit declaration of function 'LACreateNewContextWithACMContext' is invalid in C99 [-Wimplicit-function-declaration] context = LACreateNewContextWithACMContext(*externalized_context, &error); ^ /home/elife/sw/darling/src/external/openpam/pam_modules/modules/pam_localauthentication/pam_localauthentication.c:96:13: warning: incompatible integer to pointer conversion assigning to 'CFTypeRef' (aka 'const void *') from 'int' [-Wint-conversion] context = LACreateNewContextWithACMContext(*externalized_context, &error); ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ /home/elife/sw/darling/src/external/openpam/pam_modules/modules/pam_localauthentication/pam_localauthentication.c:115:10: warning: implicit declaration of function 'LAEvaluatePolicy' is invalid in C99 [-Wimplicit-function-declaration] if (!LAEvaluatePolicy(context, policy, options, &error)) { ^ /home/elife/sw/darling/src/external/openpam/pam_modules/modules/pam_localauthentication/pam_localauthentication.c:122:33: warning: implicit declaration of function 'LAVerifySEP' is invalid in C99 [-Wimplicit-function-declaration] if (!isContinuityUnlock && !LAVerifySEP(pwd->pw_uid, &error)) { ^ 4 warnings generated. [ 43%] Linking C shared library pam_localauthentication.so.2 [ 43%] Built target pam_localauthentication Consolidate compiler generated dependencies of target NetFS [ 43%] Built target NetFS Consolidate compiler generated dependencies of target sandbox_not_system [ 43%] Built target sandbox_not_system Consolidate compiler generated dependencies of target pam_mount [ 43%] Built target pam_mount Consolidate compiler generated dependencies of target pam_rootok [ 43%] Built target pam_rootok Consolidate compiler generated dependencies of target ConfigurationProfiles [ 43%] Built target ConfigurationProfiles Consolidate compiler generated dependencies of target pam_opendirectory [ 43%] Linking C shared library pam_opendirectory.so.2 Undefined symbols for architecture x86_64: "OBJC_CLASS$_NSString", referenced from: objc-class-ref in pam_opendirectory.m.o ld: symbol(s) not found for architecture x86_64 clang: error: linker command failed with exit code 1 (use -v to see invocation) src/external/openpam/pam_modules/CMakeFiles/pam_opendirectory.dir/build.make:118: recipe for target 'src/external/openpam/pam_modules/pam_opendirectory.so.2' failed make[2]: *** [src/external/openpam/pam_modules/pam_opendirectory.so.2] Error 1 CMakeFiles/Makefile2:22465: recipe for target 'src/external/openpam/pam_modules/CMakeFiles/pam_opendirectory.dir/all' failed make[1]: *** [src/external/openpam/pam_modules/CMakeFiles/pam_opendirectory.dir/all] Error 2 Makefile:135: recipe for target 'all' failed make: *** [all] Error 2

System Information clang version 6.0.0-1ubuntu2 (tags/RELEASE_600/final) Linux rtx 5.4.0-74-generic #83~18.04.1-Ubuntu SMP Tue May 11 16:01:00 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux cmake version 3.21.1 darling commit 9393db2c6ed530acaa2a4a933c391f1363fea1e8