crond: make it NOMMU-capable

crond: make it NOMMU-capable

function                                             old     new   delta
safe_setenv4                                           -      62     +62
ForkJob                                              472     511     +39
change_identity                                       21      57     +36
ParseField                                           564     571      +7
SynchronizeDir                                       178     176      -2
LogLevel                                               4       -      -4
LogFile                                                4       -      -4
FileBase                                               4       -      -4
DebugOpt                                               4       -      -4
CDir                                                   4       -      -4
DeleteFile                                           141     132      -9
packed_usage                                       24248   24228     -20
crondlog                                             157     113     -44
change_identity_e2str                                 54       -     -54
SynchronizeFile                                      729     671     -58
crond_main                                          1555    1404    -151
------------------------------------------------------------------------------
(add/remove: 1/6 grow/shrink: 3/6 up/down: 144/-358)         Total: -214 bytes