getipsecprotobyname(3NSL) synopsis is incomplete
As seen at https://illumos.org/man/3nsl/getipsecprotobyname the SYNOPSIS of getipsecprotobyname(3NSL) appears to be incomplete:
SYNOPSIS ... int getipsecprotobyname(const char *proto_name ... char *getipsecprotobynum(int proto_nump
Note the lack of closing parentheses. In addition, there's an extra word that appears in error further down:
PARAMETERS ... proto_num A pointer to a protocol number. conditions.