Gentoo's Bugzilla –
Attachment 850704 Details for
Bug 894196app-admin/cronolog-1.6.2-r5 fails to compile (MUSL-CLANG-SYSTEM): getopt.c:577:30: error: call to undeclared library function strcmp with type int (const char , const char ); ISO C99 and later do not support implicit function declarations [-Wimplicit-fun