@jperkin for https://reports.pkgci.org/SmartOS/upstream/trunk/20250703.2249/cracklib-2.9.7nb1/build.log this appears to be because #illumos still defaults to the POSIX draft declarations for getpwuid_r & getpwnam_r() in <pwd.h> instead of the final POSIX standard versions. (We changed the defaults in #OracleSolaris 11.4 to the POSIX standard versions and require defining __USE_DRAFT6_PROTOTYPES__ to get the old ones.)
You should be able to fix that with -D_POSIX_PTHREAD_SEMANTICS to get the POSIX standard forms on illumos and older Solaris releases.