A requirement on Raptor is to allow all the tools to be configurable via 
environment variables. To this end, updates have been made to extend the list 
of tools that can be configured using environment variables.

The list of new SBS_*** environment variables and their purpose is given below:

SBS_EPOCTOOLS       Directory for epoc32 tools; defaults to $EPOCROOT/epoc32/tools
                    Changes the default locations for all of the following tools.
SBS_CHECKLIB        Full path to checklib program
SBS_EFREEZE         perl, followed by full path to efreeze.pl
SBS_ELF2E32         Full path to elf2e32 program
SBS_PREPDEF         perl, followed by full path to prepdef.pl
SBS_RCOMP           Full path to rcomp program
SBS_TRANASM         perl, followed by full path to tranasm.pl
SBS_MAKEDEF         perl, followed by full path to makedef.pl
SBS_PETRAN          perl, followed by full path to petran.pl
SBS_SYMLOOKUPUTIL   perl, followed by full path to sym_lkup_util.pl
SBS_SLASHBIN        Linux only: location of /bin, i.e. an alternative location for
                    GCC and associated tools
SBS_USRBIN          Linux only: location of /usr/bin, i.e. an alternative location 
                    for Gnu tools such as the Core Utils

In the case Perl scripts (.pl files), "perl" can be replaced with the full path to 
the perl program.

The above variables supercede the following environment variables:

CHECKLIB
EFREEZE
ELF2E32
MAKEDEF
PETRAN
PREPDEF
RCOMP
TRANASM

which are no longer in use.
