If maildrop-1.5.3 is compiled with ldap support and there is no /etc/maildropldap.config file, maildrop will get SIGSEGV. Here is strace about situation:

rt_sigaction(SIGRT_31, {0x805ef00, [], SA_RESTORER|SA_RESTART, 0x42028558}, {SIG_DFL}, 8) = 0 rt_sigaction(SIGPIPE, {SIG_IGN}, {0x805ef00, [PIPE], SA_RESTORER|SA_RESTART, 0x42028558}, 8) = 0 rt_sigaction(SIGWINCH, {SIG_IGN}, {0x805ef00, [WINCH], SA_RESTORER|SA_RESTART, 0x42028558}, 8) = 0 rt_sigaction(SIGCHLD, {SIG_DFL}, {0x805ef00, [CHLD], SA_RESTORER|SA_RESTART, 0x42028558}, 8) = 0 rt_sigaction(SIGFPE, {0x805eeb0, [FPE], SA_RESTORER|SA_RESTART, 0x42028558}, {0x805ef00, [FPE], SA_RESTORER|SA_RESTART, 0x42028558}, 8) = 0 umask(07) = 022 getuid32() = 0 getgid32() = 0 getegid32() = 0 stat64("/etc/userdb.dat", 0xbfffe520) = -1 ENOENT (No such file or directory) brk(0) = 0x806f38c brk(0x807038c) = 0x807038c brk(0) = 0x807038c brk(0x8071000) = 0x8071000 open("/etc/maildropldap.config", O_RDONLY) = -1 ENOENT (No such file or directory) --- SIGSEGV (Segmentation fault) --- alarm(0) = 0 write(2, "maildrop: signal 0x", 19maildrop: signal 0x) = 19 write(2, "0", 10) = 1 write(2, "B", 1B) = 1 write(2, "\n", 1 ) = 1 _exit(75) = ?

Touching /etc/maildropldap.config fixes problem. Same problem is not available with maildrop-1.5.2 compiled with same options on same system.