1) fix_tools_exports.pl need only be run on Windows hosts; was run unnecessarily on Linux too.
2) Need to export modload.pm on Linux as well as Windows hosts.
# b1a.var
EXTENDS A1
VARIANT B1A
BUILD_INCLUDE append epoc32\include\B1\build
BUILD_INCLUDE prepend /prepend/include/B1
ROM_INCLUDE prepend /epoc32/include/B1/rom
VARIANT_HRH \epoc32/include/e32cmn.inl