djgpp: Inherit config from BASE_unix
Build failed on djgpp due to missing config vars 'AR' and 'ARFLAGS'.
Additionally, '-lz' was not added to 'lflags' when zlib support was
enabled.  Inheriting configuration variables from BASE_unix solves both
these issues.
CLA: trivial
my %targets = (
"DJGPP" => {
+ inherit_from => [ "BASE_unix" ],
CC => "gcc",
CFLAGS => "-fomit-frame-pointer -O2 -Wall",
cflags => "-I/dev/env/WATT_ROOT/inc -DTERMIOS -DL_ENDIAN",
